More and more ARM Cortex based boards appear for use by OpenSource/OpenHardware/Maker communities, and
frequently asked question in response to a new announcement is often "Is this supported by open-source toolchain?". Many people know that gcc supports ARM, including Cortex-M, very well, and many projects now lean towards using https://launchpad.net/gcc-arm-embedded as the package of their choice.
But compiler is only part of the toolchain - there should be also at
least basic hardware definition headers which would allow to access peripherals of particular chip. There was big step in that direction done by ARM Ltd, itself, by releasing CMSIS library for the Cortex-M CPU cores under open-source license, though that didn't go without controversy, see comments to that post and followup.
That's great step, but again, it's only part of the story - while it allows to access Cortex-M core registers which are common across all MCUs, there're more to MCU than just CPU - it's all the peripheral blocks. Even basic things as GPIO and timers are vendor- and model-specific, and periphery is what differentiates one vendor's offering from another's.
And other vendors don't rush to follow ARM's example, so few vendor-specific CMSIS packages are under OpenSource license (one great example of the contrary is Energy Micro EFM32 CMSIS - it's great because they open-sourced it even before ARM). One good approach to use OpenSource-friendly MCUs for your projects, and everyone is encouraged to do so. Unfortunately, that may not be practical or even possible (I wish I could by EFM32 chips in my part of the world).
So, the idea is to provide open-source MCU headers for use in OpenSource projects - until all vendors get smart to provide them. That's how libperipha project was born. Note that it's not limited to ARM Cortex-M MCUs, though support for them was a primary motivation.
There's final, small, but just as important piece which construes MCU toolchain - startup code. Without it, your application simply won't run. Another project, cortex-uni-startup (unified Cortex startup) was created to cover that. As excellent article by Ivan Sergeev explains, Cortex-M was specifically re-engineered to allow startup code to be written without any single line of assembly! cortex-uni-startup explands on this to provide easily reusable Cortex-M core startup code (usable on any Cortex-M device, but without support for peripheral-specific interrupts), then extends it to cover interrupts of particular MCU model.
These two projects are separate to cover differences in scope (cortex-uni-startup is Cortex-M specific, libperipha is unbound), licensing (cortex-uni-startup core is public domain, libperipha is BSD and others), and usage (libperipha is gross database which you probably will just want to use, then hack, cortex-uni-startup is nice learning tool of beauty of Cortex-M architecture, which you welcome to glance over before using - you won't be overwhelmed, as it's small).
Last final note - while these projects are conceived to be comprehensive, I don't have an aim to sit and add each and every possible bit of every MCU there. Instead, it is intended to be easy do add missing pieces to it on demand - right while you're working on some applied project and find such missing pieces. Then, if people find this to be indeed so, and project overall useful and contribute, then they indeed will acquire comprehensive coverage of MCUs. So, have a look, give it a try, shared feedback, spread the word, contribute patches, and overall, enjoy ;-).
Showing posts with label hardware. Show all posts
Showing posts with label hardware. Show all posts
Saturday, October 19, 2013
Sunday, October 6, 2013
Growing GPL/FOSS Loyalty Among Chinese ARM SoC Vendors
There are visible changes in how Chinese ARM SoC vendors deal with Open Source license compliance (words) and Open Source software at all (spirit) during this year. Not only western resellers of devices based on Chinese SoCs release GPL compliance packages, but many popular SoC companies themselves established GPL compliance/loyalty/support pages. Few go beyond just adhering to word of GPL by releasing kernel source blobs (by blobs I means large tarballs devoid of any development history and support files), but also establish git repositories, release Android trees, set up public bugtrackers.
Of course, they are still not exactly GPL compliant - scrutiny of any releases would likely show missing parts, binary objects for drivers, etc. But there's definitely a difference between plucking out WiFi driver out of flash image you have on you device and downloading "official binary" from a SoC vendors. It's also a good start, and there's a hope the situation with complete source availability will improve. And as everyone watching the area knows, the industry at the whole needs to improve - Western companies may comply with GPL by providing source for kernel shims, but that doesn't help users to support vendors' hardware if they just move binary blobs to userspace.
The changes discussed didn't come by themselves and at once. Lot of people paved the road to this via gpl-violations.org, via various leaks, etc. But critical change came with emergence of Open Hardware startups. They are led by people who strongly believe in Open paradigm, but also to do their ODM-like business, they need to provide sufficient documentation/sources to the customers. So they have little choice but request that from upstream SoC vendors, in redistributable form. So, thanks Rhombus-Tech, Olimex, Cubitech!
Anyway, here're the links to Chinese companies' GPL loyalty pages I know so far. Additions and corrections are welcome.
And as extra, community projects to support some of vendor SoCs from above list:
Of course, they are still not exactly GPL compliant - scrutiny of any releases would likely show missing parts, binary objects for drivers, etc. But there's definitely a difference between plucking out WiFi driver out of flash image you have on you device and downloading "official binary" from a SoC vendors. It's also a good start, and there's a hope the situation with complete source availability will improve. And as everyone watching the area knows, the industry at the whole needs to improve - Western companies may comply with GPL by providing source for kernel shims, but that doesn't help users to support vendors' hardware if they just move binary blobs to userspace.
The changes discussed didn't come by themselves and at once. Lot of people paved the road to this via gpl-violations.org, via various leaks, etc. But critical change came with emergence of Open Hardware startups. They are led by people who strongly believe in Open paradigm, but also to do their ODM-like business, they need to provide sufficient documentation/sources to the customers. So they have little choice but request that from upstream SoC vendors, in redistributable form. So, thanks Rhombus-Tech, Olimex, Cubitech!
Anyway, here're the links to Chinese companies' GPL loyalty pages I know so far. Additions and corrections are welcome.
And as extra, community projects to support some of vendor SoCs from above list:
Friday, June 28, 2013
Links for June 2013
- PCB design for high pin count SMD components: ever wondered why they "stupidly" don't put via in BGA pads? Here's why, vividly explained: http://blog.screamingcircuits.com/via_in_pad.html (other blog posts are insightful too).
Sunday, June 9, 2013
Buffalo SkyStation CWR-GN150S Teardown
Walking last few hours thru Hong Kong streets and molls during last visit, I was looking for some impulsive shopping, and bought micro-router having following labels: Buffalo SkyStation CWR-GN150S, Hornington NE-GN150S, etc. What lured me was its really small size (5.5x4.5x1.7cm) and 2 Ethernet ports. It was also couple of bucks cheaper than TL-WR703N. I was thinking where's the catch, and later got it - it doesn't have USB host port (micro USB it has is only for power).
All manual for the router is in Japanese/Chinese, same for firmware, no English firmware on Internets, actually, barely any English pages at all. Teardown was even more disappointing: it has only 16MB of RAM (bye, OpenWRT), and turned out it uses RTL8196C SoC, infamous for being of MIPS-Lexra architecture, which is MIPS subarch crippled due to patent trolling between MIPS vendors. There's barely any support for this subarch from gcc and OpenSource projects, I found just one brave guy who tries to change the situation:
All manual for the router is in Japanese/Chinese, same for firmware, no English firmware on Internets, actually, barely any English pages at all. Teardown was even more disappointing: it has only 16MB of RAM (bye, OpenWRT), and turned out it uses RTL8196C SoC, infamous for being of MIPS-Lexra architecture, which is MIPS subarch crippled due to patent trolling between MIPS vendors. There's barely any support for this subarch from gcc and OpenSource projects, I found just one brave guy who tries to change the situation:
- http://ncrmnt.org/wp/2011/08/30/rtl8196-vs-openwrt-2/
- https://github.com/nekromant/linux-rlx-upstream
Sunday, December 9, 2012
Links for December 2012
- Energy Micro EFM32 "Tiny Gecko" Developer Board - Impressions and open source tools usage thinking
- EFM32STK linux toolchain - Blogpost on using EFM32STK under Linux
- https://launchpad.net/gcc-arm-embedded - Cortex-M targeted toolchain from Ubuntu developers, binary tarball releases
- J-Link downloads -Tools/drivers for JTAG/SWD controller as included in EFM32STK boards, including for Linux
- EnergyMicro downloads - Official EnergyMicro downloads, including Linux tools
Tuesday, September 11, 2012
Links for September 2012
- Arduino-IRremote multi-protocol IR library
- MSP430G2xxx parametric search (also, parametric search for other TI MCU families)
Thursday, March 29, 2012
Developing for TI LaunchPad MSP430 board on Ubuntu
If you google for it, you'll find quite a few blog posts, but most of them are from 2010. But starting with Ubuntu 11.10 (Oneiric), gcc-msp430 and friends are included in the main repositories, so you can just apt-get install them:
There's one annoying bug in Oneiric's version of binutils-msp430 which breaks build with -ffunction-sections -Wl,--gc-sections options (which is kinda common trick in embedded world to remove unused functions and reduce code size): mspgcc #3386145. It is fixed in Ubuntu 12.04 (Precise).
I'm however still running Maverick, so instead I downloaded following Oneiric packages:
Then few from Precise:
(If you try to install Precise versions of other packages on Maverick, they want to pull upgrades to system libs, which I wanted to avoid).
and installed them manually with dpkg.
apt-get install binutils-msp430 gcc-msp430 \
msp430-libc msp430mcu mspdebug
There's one annoying bug in Oneiric's version of binutils-msp430 which breaks build with -ffunction-sections -Wl,--gc-sections options (which is kinda common trick in embedded world to remove unused functions and reduce code size): mspgcc #3386145. It is fixed in Ubuntu 12.04 (Precise).
I'm however still running Maverick, so instead I downloaded following Oneiric packages:
binutils-msp430_2.21~msp20110421-2_i386.deb gcc-msp430_4.5.3~mspgcc-4.5.2-20110612-1_i386.deb libgmp10_5.0.1+dfsg-7ubuntu2_i386.deb libmpc2_0.9-3_i386.deb msp430-libc_20110612-1_i386.deb mspdebug_0.16-1_i386.deb
Then few from Precise:
binutils-msp430_2.22~msp20110716p5-1_i386.deb msp430mcu_20110613-3_all.deb
(If you try to install Precise versions of other packages on Maverick, they want to pull upgrades to system libs, which I wanted to avoid).
and installed them manually with dpkg.
Wednesday, March 28, 2012
Connetcing to preprogrammed TI Launchpad demo under Linux
TI Launchpad board comes with preprogrammed demo application for temperature sensing which is touted to output temperature values to host via USB-encapsulated UART. By connecting to it via terminal you can see that it indeed sends something, but that doesn't look anything like temperature represent in ascii digits, like someone naively could expect. It turns out that it's well kept secret on Launchpad wiki pages how to make sense out of it - at least, you get advertisements for CCS and Java-based GUIs to read out the output, but not straight docs of how to use builtin demo without all those crutches. So well, wrong approach - it's your random user-friendly arduino, approach of reading docs doesn't work here, better go straight to the source.
And, here's step by step instructions:
First thing to note is that Launchpad's UART-via-USB emulation is extremely fragile. It seems that if MCU started to produce UART output but host doesn't read it out, then buffer in USB bridge just gets overflowed and it stops responding to USB. So, if you want to get it working, follow each step below precisely and if any issue happens, restart from beginning (with unplugging LaunchPad).
And, here's step by step instructions:
First thing to note is that Launchpad's UART-via-USB emulation is extremely fragile. It seems that if MCU started to produce UART output but host doesn't read it out, then buffer in USB bridge just gets overflowed and it stops responding to USB. So, if you want to get it working, follow each step below precisely and if any issue happens, restart from beginning (with unplugging LaunchPad).
- If you have plugged LaunchPad into USB, unplug it now to make sure you start with properly reset device.
- Plugin the board into USB, general-purpose green and red should blink interchangeably. The demo app doesn't yet sense temperature or sends it out yet in this mode.
- Execute stty 2400 -F /dev/ttyACM0 . That's right - the demo app communicates at 2400 bit/s data rate and using any other rate will produce garbage input. (One reason for such low speed is that LaunchPad's MCU actually doesn't have hardware UART, it is emulated in software).
- Run hexdump -v -C /dev/ttyACM0 . It shouldn't produce any output yet.
- Press GPIO button. The demo app goes into measurement mode and starts to send out temperature in Fahrenheit as raw bytes over UART. Try to heat/cool air around the board to see values change.
00000020 60 60 60 60 60 60 60 60 60 60 60 60 60 60 60 60 |````````````````| 00000030 60 60 60 60 60 60 60 60 60 60 60 60 60 60 60 60 |````````````````| 00000040 60 60 60 60 60 60 60 60 60 60 61 60 60 61 60 60 |``````````a``a``| 00000050 61 60 60 61 61 61 60 61 61 61 61 61 61 61 61 61 |a``aaa`aaaaaaaaa| 00000060 61 61 61 61 61 62 61 62 62 62 62 62 62 62 62 61 |aaaaababbbbbbbba| 00000070 62 62 62 62 62 62 62 62 62 62 62 62 62 62 62 62 |bbbbbbbbbbbbbbbb| 00000080 62 62 62 62 62 62 62 62 62 62 62 62 62 62 62 62 |bbbbbbbbbbbbbbbb|
Sunday, January 29, 2012
HC-04 Bluetooth module and BlueCore4 Deep Sleep
The good news is that BlueCore indeed has Deep Sleep mode, it's not marketing hype. It can be verified by configuring PSKEY_CLOCK_REQUEST_ENABLE to drive PIO when chip uses/doesn't use external clock. The key here is not to keep PSTool run (which well, you need to tweak sleep settings).
The bad news is that an HC-04 module in Deep Sleep still consumes 2.5mA, which is far too high for anything called Deep Sleep. So, something on the module besides BlueCore still consumes too much power. However, when BlueCore is held in reset state, entire module consumes 0.
Without Deep Sleep, simple LED flash task consumes 3.5mA, so there's not that much gain from the Deep Sleep...
The bad news is that an HC-04 module in Deep Sleep still consumes 2.5mA, which is far too high for anything called Deep Sleep. So, something on the module besides BlueCore still consumes too much power. However, when BlueCore is held in reset state, entire module consumes 0.
Without Deep Sleep, simple LED flash task consumes 3.5mA, so there's not that much gain from the Deep Sleep...
Tuesday, January 17, 2012
New Hack Toy - Zenithink ZT-180
Recently I got new hack toy: cheap (well, depends) Chinese Zenithink ZT-180 tablet. This one seem to be (have been) pretty popular and hacker-friendly. Here's data about it:
Button combinations to hold during power on:
Random links:
- Vendor: http://zenithink.com/
- Product home page, ZT180-102 (it's the oldest in the product list, so soon will go to "Retired products" (== /dev/null))
- CPU: IMAPx200 (or IMAPx210, IMAPx220), ~1GHz
- GPU (SoC-builtin): GC600 (tentative)
- RAM: 512MB (Android boots with mem=384M)
- Bootloader: u-boot
- Kernel source from the vendor (github)
- Slatedroid forum announcement and discussion about the kernel release above
- Vendor toolchain
- Post saying that user yuray started upgrading kernel to 3.0.4. Following posts add more details, no source link provided.
- yuray also appears to be the author of ZT-180-Linux-Flash-Tool.
- Slatedroid ZT-180 Wiki
- More detailed hacking information
Button combinations to hold during power on:
- Home+Power - Upgrade firmware from /sdcard/zt-update/
- Left arrow (of swing double-button)+Power - Boot with debug kernel from /sdcard/zt-debug/ . Debug kernel is booted and continues with the normal boot process.
- Right arrow (of swing double-button)+Power - Multiboot support, select one of 3 modes:
- Android adb - kernel with ADB over USB support
- Android mass storage - kernel with mass storage USB gadget support (tablet is presented as a mass storage when connected to host)
- Other OS - WinCE
Random links:
- http://www.slatedroid.com/topic/10233-zenithink-zt-180-cpu-actually-infotmic-imap210-cpu/
- http://www.androidtablets.net/forum/infotmic-based/2354-infotmic-chips.html
Saturday, November 12, 2011
Shopping for 3D TV...
Shopping for 3D TV (again), few findings:
- There are no non-LED 3D TVs for sale in this part of world anymore (in particular, my older favorite, LE40C750 is no longer available)
- Samsung D6xxx series (the cheapest) were caught red-handed not providing FullHD resolution in 3D: via Samygo. (Note from myself: Samsung was caught because lots of people actually buy their stuff, what one can think about other vendors?)
- LG goes out of line of vendors with 3D shutter glasses technology with their FPR ("Cinema 3D" in marketing speak) technology. It uses passive (no power needed) polarized glasses, like RealD cimenas. Announced April (on these longitudes), already in local shops at not-so-indecent prices. FPR is Film Patterned Retarder, and I hope the last word is spelled right, because I have high hopes for this tech. It shares the same issue as Samsung D6xxx: there won't FullHD here for sure, but at least it's official and there're other benefits.
Sunday, October 23, 2011
Fixing fan cooler in Asus X34F notebook
I spent good deal of day today fixing howling, growling, roaring and making other unpleasant noises fan in my Asus X34F notebook. X34F appears to be region-specific version of U35F, and motherboard bears labels of UL30A, so I guess this may be pertinent to them either.
I wasn't able to find a service manual, so I proceeded with disassembly by experience and intuition. It turns out that to detach cooler one needs to unscrew one motherboard plate completely (there're two, bound with a connector). The cooler part number turned out to be KDB04505HA by Delta Electronics. Vendor site showed no trace of this part no. But quick googling showed that it's the same part no used in Macbook Pro with similar performance stories. One another reason you don't need to pay a lot to get the same c.r.a.p.
Once I completely detached it, I figured how it could make those noises - impeller could dance on its axis, and while doing so could touch plastic casing. So, my idea was to either cut the corresponding side of impeller, or increase vertical space in which it "dances". I went for the latter, adding two washers between metal and plastic casing parts and gluing another washer on third point to get more support.
I decided also to oil fan, and considering oiling with machine oil could lead to just more dust accumulation, figure I take a pencil and oil it with graphite. Big mistake - either that pencil didn't really have pure graphite, or I put it there too much, but after re-assembling and powering all stuff, I saw that the cooler stopped working at all.
I almost gave up and started to look for closest repair shop, then figured I already have thing half-disassembled, and they would need to extract the fan anyway, so guessed I do it myself and deliver it to repairman in pieces. But before then, heck, I'll make another pass it it - first of all, try to power it on despite its rather home-use unfriendly connector.
Couldn't reliably figure the connector pinout (found pinout only for 12V desktop fans, who knows if laptop one would be proprietary), so tried googling for wire color codes instead. This page gave me good hints (black - GND, red - VCC, blue - PWM for speed control, yellow or another - speed sensor) which I decided to try with power supply at last. Unfriendly connector? Was able to stick into it breadboard wires, then breadboard, then breadboard power adapter. Saw the motor nudge, as struggling with friction. Took off the impeller, wiped its axis, and cleaned other part as best as I could. Put it back and powered, and so it moving - but, with whistling and vibration, even though suspected plastic part was off. Well, decided there's little to lose and oiled it with smallish drop of machine oil.
That was it! The thing stopped its hellish screams and just monotonically buzzed if move ear close to it. Reassembled all the stuff - the noise level is close to that which was when I bought it, as far as I can tell. acpitz sensor temperature is down to 55dC from 95dC I saw before. Finger crossed that oiling will help for decent time.
Conclusion and note to myself: It's indeed nice idea to be in power of your hardware, no doubts, and fears off. And its better to invest into tools than to pay for services of unknown quality (could easily imagine the same oiling to be done, but charged as replacement).
UPDATE: No, it didn't last even a day :-(
I wasn't able to find a service manual, so I proceeded with disassembly by experience and intuition. It turns out that to detach cooler one needs to unscrew one motherboard plate completely (there're two, bound with a connector). The cooler part number turned out to be KDB04505HA by Delta Electronics. Vendor site showed no trace of this part no. But quick googling showed that it's the same part no used in Macbook Pro with similar performance stories. One another reason you don't need to pay a lot to get the same c.r.a.p.
Once I completely detached it, I figured how it could make those noises - impeller could dance on its axis, and while doing so could touch plastic casing. So, my idea was to either cut the corresponding side of impeller, or increase vertical space in which it "dances". I went for the latter, adding two washers between metal and plastic casing parts and gluing another washer on third point to get more support.
I decided also to oil fan, and considering oiling with machine oil could lead to just more dust accumulation, figure I take a pencil and oil it with graphite. Big mistake - either that pencil didn't really have pure graphite, or I put it there too much, but after re-assembling and powering all stuff, I saw that the cooler stopped working at all.
I almost gave up and started to look for closest repair shop, then figured I already have thing half-disassembled, and they would need to extract the fan anyway, so guessed I do it myself and deliver it to repairman in pieces. But before then, heck, I'll make another pass it it - first of all, try to power it on despite its rather home-use unfriendly connector.
Couldn't reliably figure the connector pinout (found pinout only for 12V desktop fans, who knows if laptop one would be proprietary), so tried googling for wire color codes instead. This page gave me good hints (black - GND, red - VCC, blue - PWM for speed control, yellow or another - speed sensor) which I decided to try with power supply at last. Unfriendly connector? Was able to stick into it breadboard wires, then breadboard, then breadboard power adapter. Saw the motor nudge, as struggling with friction. Took off the impeller, wiped its axis, and cleaned other part as best as I could. Put it back and powered, and so it moving - but, with whistling and vibration, even though suspected plastic part was off. Well, decided there's little to lose and oiled it with smallish drop of machine oil.
That was it! The thing stopped its hellish screams and just monotonically buzzed if move ear close to it. Reassembled all the stuff - the noise level is close to that which was when I bought it, as far as I can tell. acpitz sensor temperature is down to 55dC from 95dC I saw before. Finger crossed that oiling will help for decent time.
Conclusion and note to myself: It's indeed nice idea to be in power of your hardware, no doubts, and fears off. And its better to invest into tools than to pay for services of unknown quality (could easily imagine the same oiling to be done, but charged as replacement).
UPDATE: No, it didn't last even a day :-(
Wednesday, October 19, 2011
Making hcitool commands work
It's a shame how some now-ubiquitous technologies, like Bluetooth, are under-used and under-understood. And by usage I don't mean here occasional business card exchange, net access, being bluesnarfed and other boring consumer-level activity, but page scans, inquiries and having secure wireless communication you can trust (or not).
Anyway, if you ever tried using hcitool you may think it barely works. For example:
Ok, so here's the matter. First of all, hcitool accesses hci device directly, and that requires root access. Secondly, it works on low protocol level (ACL), so connection established by "cc" is of course not pairing or service-level connection. It's low level connection, which persist only while data is transferred and shutdown quickly to preserve the power. Yep, it shuts down while you type or even re-run next command. That's how it should be done:
More fun:
Anyway, if you ever tried using hcitool you may think it barely works. For example:
# hcitool cc <bdaddr>
# hcitool lq <bdaddr>
Not connected.
Ok, so here's the matter. First of all, hcitool accesses hci device directly, and that requires root access. Secondly, it works on low protocol level (ACL), so connection established by "cc" is of course not pairing or service-level connection. It's low level connection, which persist only while data is transferred and shutdown quickly to preserve the power. Yep, it shuts down while you type or even re-run next command. That's how it should be done:
# hcitool cc <bdaddr>; hcitool lq <bdaddr>
Link quality: 255
More fun:
# hcitool cc $BDADDR; hcitool auth $BDADDR; hcitool enc $BDADDR; hcitool key $BDADDR; hcitool con
Connections:
< ACL 7D:75:75:xx:xx:xx handle 12 state 1 lm MASTER AUTH ENCRYPT SECURE
Monday, June 27, 2011
Links for June 2011
- http://sigrok.org/ - OpenSource logic analyzer software supporting lot of hardware analyzers (C++/Qt, protocol plugins in Python)
- http://dangerousprototypes.com/2010/07/23/logic-analyzer-client-roundup/ - Logic analyzer client roundup
- http://blog.visucore.com/categories/embedded - Blog posts about using and hacking USBee SX. In particular, how to find UART pins on a device using it; how to replace firmware with self-compiled using SDCC, etc.
- http://openenergymonitor.org/ - Open Energy Monito
- On accuracy of (commercially available) power meters:
- Lies, Damn Lies and Cheap Power Meters
- That one lying disassembled with blob chip, but with potentiometers to calibrate
- Comparing KaW and a clone with industrial piece
- http://www.pupman.com/listarchives/2005/Aug/msg00936.html
Sunday, June 26, 2011
Hacking Luxeon SP-1
I finally going to get Arduino, and while I'm choosing flavor and waiting for it, I can't help but disassembling all devices I have at home, each time speaking: "This must have Arduino inside!" (meaning of course that I expect it to be based on general-purpose MCU). Gosh, I usually get "blob chip" (uncased chip with blob of epoxy on top).
Well, I finally had my expectations fulfilled - Luxeon SP-1 voltage stabilizer/cutter features ATMEGA48V-10PU (Flash: 4k, EEPROM: 256, RAM:512). Not only that, it is installed in DIP socket! Buy from Luxeon, they're hacker-friendly ;-).
I bought the device actually for a wattmeter it features (which fact is hard to figure out from common specs found in the shops, I accidentally read somebody mentioning it on a forum). The wattmeter is of course not bright - for a lamp rated 100W it shows 88W, and for more powerful equipment (like perforator) understates wattage even more (maybe it's difference between real and apparent power factor).
Still, for $17 you get Arudino-alike with voltage/current sensor and hacking possibility. Woot!
BOM:
High-power board:
Well, I finally had my expectations fulfilled - Luxeon SP-1 voltage stabilizer/cutter features ATMEGA48V-10PU (Flash: 4k, EEPROM: 256, RAM:512). Not only that, it is installed in DIP socket! Buy from Luxeon, they're hacker-friendly ;-).
I bought the device actually for a wattmeter it features (which fact is hard to figure out from common specs found in the shops, I accidentally read somebody mentioning it on a forum). The wattmeter is of course not bright - for a lamp rated 100W it shows 88W, and for more powerful equipment (like perforator) understates wattage even more (maybe it's difference between real and apparent power factor).
Still, for $17 you get Arudino-alike with voltage/current sensor and hacking possibility. Woot!
BOM:
High-power board:
- Relay: Coil: 24VDC, 5A/240VAC
- 7805
- Coil transformer LR-019B
- ATMEGA48V-10PU
- 2 buttons
- 2 LEDs (red & green)
- 3-digit 7-segment LED indicator
Hacking Technoline WS 585 weatherstation
Technoline WS 585 is a simple consumer weatherstation offering builtin indoor temperature sensor and outdoor wireless (433MHz) temperature sensor. But as funny extra, it comes with wireless USB dongle which, being attached to computer running special (Windows) software, transmits to the base station weather forecast for next few days as well as extra weather data for today.
There're two problems with that: I prefer my weather forecast site, not one hardcoded by the vendor, and, I don't have constantly running Windows box. Besides, this device is essentially low-resolution wireless LCD (albeit with funny pixel shape), so one may want to show build status or loadavg on it.
So, I wanted to hack a Linux driver for it for a long time. Wider-scope, I wanted to grok USB and hack driver for it for longer time. Few times before I had a look at usbsnoop log of something, It seemed for overwhelming and I didn't really put much effort into it.
So well, I read up USB docs (Usb in a NutShell is a good summarization of the spec), and started to look at USB descriptors and logs with understanding eye.
Here are info and descriptors for WS585 dongle btw:
dmesg:
[1118327.253222] usb 2-1.3: new low speed USB device using ehci_hcd and address 3 [1118327.524340] usbcore: registered new interface driver hiddev [1118327.527975] input: Tenx Non standard Device as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.3/2-1.3:1.0/input/input51 [1118327.528162] generic-usb 0003:1130:0202.0001: input,hidraw0: USB HID v1.10 Device [Tenx Non standard Device] on usb-0000:00:1d.0-1.3/input0 [1118327.530011] input: Tenx Non standard Device as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.3/2-1.3:1.1/input/input52 [1118327.530182] generic-usb 0003:1130:0202.0002: input,hidraw1: USB HID v1.10 Device [Tenx Non standard Device] on usb-0000:00:1d.0-1.3/input1 [1118327.530554] usbcore: registered new interface driver usbhid [1118327.530557] usbhid: USB HID core driver
lsusb:
Bus 002 Device 003: ID 1130:0202 Tenx Technology, Inc.
lsusb -v:
Device: ID 1130:0202 Tenx Technology, Inc.
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x1130 Tenx Technology, Inc.
idProduct 0x0202
bcdDevice 1.00
iManufacturer 0
iProduct 2 Tenx Non standard Device
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 59
bNumInterfaces 2
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 3 Human Interface Device
bInterfaceSubClass 0 No Subclass
bInterfaceProtocol 0 None
iInterface 0
HID Device Descriptor:
bLength 9
bDescriptorType 33
bcdHID 1.10
bCountryCode 0 Not supported
bNumDescriptors 1
bDescriptorType 34 Report
wDescriptorLength 41
Report Descriptors:
** UNAVAILABLE **
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0008 1x 8 bytes
bInterval 10
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 3 Human Interface Device
bInterfaceSubClass 0 No Subclass
bInterfaceProtocol 0 None
iInterface 0
HID Device Descriptor:
bLength 9
bDescriptorType 33
bcdHID 1.10
bCountryCode 0 Not supported
bNumDescriptors 1
bDescriptorType 34 Report
wDescriptorLength 23
Report Descriptors:
** UNAVAILABLE **
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0008 1x 8 bytes
bInterval 10
Device Status: 0x0000
(Bus Powered)So, it uses well-known programmable microcontroller chip from Tenx Technology, found in bunch of other devices like USB missile launchers, etc.
By the end of day I had a PyUSB app which implemented the protocol seen in usbsnoop log. It received all the same (way, similar) responses from the chip. But it didn't exhibit external behavior. Specifically, under Windows, LED on the dongle blinks about every 55s (sic, less than whole minute), and right at the same time weather station updates its display. Under Linux with my app, LED never blinks, and no updates are shown on the display. I tried to to adjust my app to use the same delays between requests as seen in the original log, but no avail.
So, I have 2 ideas here: I made some mistake transcribing log into PyUSB calls, or, it's all timing related, and I didn't get the timing right. I tried to capture USB log around the blink, and don't see any request which could make explicit "transmit" request. I have following hypothesis: base station doesn't listen air all the time, it turns on it radio only ~ once a minute. So, dongle at first synchronizes to the base station. Then, it just transmits data at predefined intervals. And control requests from host don't transmit stuff immediately, but put it into buffer for the next transmission.
Is that true or not, hard to tell. But this device is for sure more complicated than other Tenx-based ones due to its wireless and trickle-transmit features.
I've put my current code together with USB logs to git at https://gitorious.org/homeauto/homeauto-devices
Sunday, February 27, 2011
WM8505 (VT8500, WM85xx) hacking timeline
I've got my hands on cheap WM8505-based Android tablet, figuring out how open to hacking it is, as usual, the information is fragmented and outdated, so I'm going to try and compile timeline:
- 2010-05-28 Alexey Charkov makes first commit to the tree hosted at http://gitorious.org/linux-on-via-vt8500
- 2010-06-03 Alexey Charkov registers http://gitorious.org/linux-on-via-vt8500
- 2010-06-03 Angus Gratton's first blog post on Eken M001, Eken M001 Android tablet review (Pt 1)
- 2010-06-10 Angus Gratton Notes on porting Android 2.x to Eken M001 Discusses the fact the Android userspace was patched to use libwmtapi.so
- 2010-06-22 Angus Gratton Eken M001 teardown & serial console Show good internal pictures (in particular, "WM8505" lebel on CPU).
- 2010-06-13 created topic Kernel source almost available
- 2010-07-27 Harald Welte released initial packages from VIA, with binary objects for video and SD/MMC drivers
- 2010-07-28 Angus Gratton's follow-up on inial VIA release
- 2010-08-01 Angus Gratton created topic WM8505 linux kernel development (for Eken M001 & others).
- 2010-08-01 https://github.com/projectgus/kernel_wm8505 created
- 2010-08-06 Alexey Charkov invites Angus Gratton to join forces on clean implementation of wm850x support at http://gitorious.org/linux-on-via-vt8500/vt8500-kernel
- 2010-08-13 Harald Welte posts about making Android 2.6.29 kernel source available. That tarball actually has C source in drivers/video/wmt .
- 2010-08-18 Angus Gratton announces (blog) creation of VT8500/WM8505 Linux Kernel Google Group. "Kernel discussion seems to have running in a few different places concurrently, especially between netbook & tablet people."
- 2010-09-16 Angus Gratton created topic Testing: Custom kernel with cpu frequency scaling/overclock enabled.
- 2010-11-24 Angus Gratton: Froyo (Android 2.2) alpha for Eken M001 & M003
- https://github.com/projectgus/kernel_wm8505 - import and cleanup of original VIA sources, maintained by Angus Gratton
- http://gitorious.org/linux-on-via-vt8500 - from-scratch and cleaned up implementation maintained by Alexey Charkov
- https://github.com/bushing/android_wm8505 - just a few commits, last 2010-06-03, apparently superseded by other repos
Friday, January 21, 2011
And the winner is...
After problem with MSI X430 described in earlier post, I kept shopping. There were few interesting contenders. By chance I saw in the shop a ViewSonic ViewBook Pro VNB131. I didn't even consider a ViewSonic to be a company to consider notebooks from, but they keep providing surprises. The screen immediately catches attention - it's truly bright and vivid, unlikely washed-out generation of current inexpensive notebook screens. And in around 1.6kg they managed to cramp even easily-replaceable DVD. Which is a brilliant ... drawback, in the same way as big battery in notebook is ;-). DVD in my nx9420 is amost dead now, hardly reading every 5th disk I put into it (which is rare nowadays).
Well, anyway, VNB131 is outstanding device (they even promise all-aluminum frame), exactly of that type that you notice, keep in mind, and when finally you want to get one few months later - oops, it's no longer around. The reason I skipped it was that I got idea of L335 performance, and looked up Core2 ULV (used in VNB131) performance - it turned out it's not much better than 5-year old Toshiba M200 which I have. As I got idea taht i won't get anything decent for $500, I decided to shell out more, but get something noticeably powerful than even nx9420.
And the winnder was Asus X34F, which just recently got into stock around. X34F is a strange device, there was no info about it on Asus site. No reviews on the net. Googling just gave lot of pricelist hits clustered for some locality, giving good, though sometimes controversial specs. After extensive research, it turned out it's a U35F spinoff for these localities. Afre finally spotting an instance in a physical shop, I've ordered it and it seems everything is right with it. Funny thing, scrolling with touchpad again doesn't work with Ubuntu 10.10 (device otherwise sells with just FreeDOS). But I have high hopes and trust Asus not to stick films advertising 2-finger scroll on an unsupporting touchpad. Just Linux driver needs upgrade or maybe hacking. After all, I already fixed (thanks to forums) hang-on-suspend issue which at first occured.
Well, anyway, VNB131 is outstanding device (they even promise all-aluminum frame), exactly of that type that you notice, keep in mind, and when finally you want to get one few months later - oops, it's no longer around. The reason I skipped it was that I got idea of L335 performance, and looked up Core2 ULV (used in VNB131) performance - it turned out it's not much better than 5-year old Toshiba M200 which I have. As I got idea taht i won't get anything decent for $500, I decided to shell out more, but get something noticeably powerful than even nx9420.
And the winnder was Asus X34F, which just recently got into stock around. X34F is a strange device, there was no info about it on Asus site. No reviews on the net. Googling just gave lot of pricelist hits clustered for some locality, giving good, though sometimes controversial specs. After extensive research, it turned out it's a U35F spinoff for these localities. Afre finally spotting an instance in a physical shop, I've ordered it and it seems everything is right with it. Funny thing, scrolling with touchpad again doesn't work with Ubuntu 10.10 (device otherwise sells with just FreeDOS). But I have high hopes and trust Asus not to stick films advertising 2-finger scroll on an unsupporting touchpad. Just Linux driver needs upgrade or maybe hacking. After all, I already fixed (thanks to forums) hang-on-suspend issue which at first occured.
Wednesday, January 5, 2011
Notebook MSI X430 (aka X420 aka X410) - Big Disappointment
So, I've been shopping for notebook for some time - my current work model, HP Compaq nx9420, has been failing me for like 1.5yrs now, with its lid hanging on just one corner (the steel support plate in there broke, nice job, HP!). I also grew pretty tired to carry it's 3.3kg around, so was shopping for subnotebook. So, criteria was: minimal weight, workable screen size (12" is kinda small, 14" is kinda heavy, those are extreme bounds), budget price (also tired to shell out a grand+, especially that nx9420 shows that no matter how much you pay, you have strong chance to get budget quality nowadays).
I had Acer Timeline t3810 (or something close) in my shopping list, but was swamped by real world, so when I came closer to actual shopping - oops, that model is no longer available. That's another trait of modern hardware market - it's not like good stuff gradually becomes cheaper and better stuff comes in, it's like good stuff being replaced by more expensive and mediocre one.
So, I started looking for another replacement, and I found MSI X430. Gosh, it was brilliant. They cramped 14" in 1.5kg - there was/is no competitor in that regard. Battery life was crap (~2hrs), but that's actually brilliant engineering thought. Because laptop battery doesn't last "X or Y hours", it lasts untill next hot summer - when it completely dies. So, it makes little sense to pay lot for large battery which will anyway die soon. So, thanks to that nice crappy battery, X430 costed just $500 (my ideal upper bound for a contemporary piece of technical stuff), it made decent weight to of course. The performance wasn't great, but at least it had latest AMD X2 which has come to these vicinities, L335.
Guess what - when I started to actually call shops, it turned out the model went out of stock like a week ago. Yes, it was on hot sale the whole summer, and boom, suddenly there's only X410 & X420 which are less performance and/or much more pricey. Well, I waited a bit, and oh, miracle - one shop got it back.
Got it in a day, just to find out that:
No, I will not. I'm not keen on returning stuff, but that box went back to the shop. And I even wrote this blog post ;^).
I had Acer Timeline t3810 (or something close) in my shopping list, but was swamped by real world, so when I came closer to actual shopping - oops, that model is no longer available. That's another trait of modern hardware market - it's not like good stuff gradually becomes cheaper and better stuff comes in, it's like good stuff being replaced by more expensive and mediocre one.
So, I started looking for another replacement, and I found MSI X430. Gosh, it was brilliant. They cramped 14" in 1.5kg - there was/is no competitor in that regard. Battery life was crap (~2hrs), but that's actually brilliant engineering thought. Because laptop battery doesn't last "X or Y hours", it lasts untill next hot summer - when it completely dies. So, it makes little sense to pay lot for large battery which will anyway die soon. So, thanks to that nice crappy battery, X430 costed just $500 (my ideal upper bound for a contemporary piece of technical stuff), it made decent weight to of course. The performance wasn't great, but at least it had latest AMD X2 which has come to these vicinities, L335.
Guess what - when I started to actually call shops, it turned out the model went out of stock like a week ago. Yes, it was on hot sale the whole summer, and boom, suddenly there's only X410 & X420 which are less performance and/or much more pricey. Well, I waited a bit, and oh, miracle - one shop got it back.
Got it in a day, just to find out that:
- Max amount of memory ambgiously (not explicitly) mentioned in the docs is 2Gb. Come on, this is not netbook, which 2Gb?? And it doesn't have dedicated RAM cover to easily try 4Gb module - would need to disassemble it completely (either void warranty or go to service center - with what - 4Gb SODIMM I purchased not knowing if it works or not?)
- Booted Ubuntu 10.10. Got complete mess on the screen, more specifically torn off signal sync. Remember how old CRT TVs looked with broken row sync heterodyne? I couldn't even imagine that effect can be so faithfully reproduced on LCD panel! I was able to found just single report of someone else facing that, did some hacking, found a workaround, and then thanks to DRM driver people found easy solution. So, well, that DRM/Ubuntu issue, though, taking into account all points above and below, MSI engineers outwitted themselves too. (Support for such funky videoadapeters, as in X430, will be (was) fixed in next kernel version).
- One final point which really put me over the edge and made me return the thing. Its touchpad doesn't support scrolling. Well, to be exact, it does, in a following manner: you have to tap at top right corner to scroll up, somewhere near bottom right corner to scroll down. So yes, you had to target the tap, and target pretty carefully, requiring an eye-look. How that compares with familiar blind swipe near the right side? If that sounds like a petty complaint, you've got to use that yourself! Remember, I started all ecstatic about the box, and that dissatisfaction grew subconscious ways. It's like making you walk on the knees. Many people would say "So what? Connect any mouse you like, voila!" Well, but I'm buying a subnote to be light and lean and not carry extra stuff, and still being able to use it comfortably. If to start bringing around crutches everywhere, why bother with lack of selection, higher price, lower performance of subnote? Well, I started to drop into any notebook shop I saw in city motion and know what - all notebooks out there have sane touchpad scrolling, newer ones brag about multi-touch (2-finger) scrolling with stickers, couple of MSI models were the only ones with such brain-dead scrolling. I finally made a search over the Internet. And found dozen-of-pages hate-topics regarding MSI's touchpads. People go by any length to do something with them, like soldering out that thing and solder in normal touchpad.
No, I will not. I'm not keen on returning stuff, but that box went back to the shop. And I even wrote this blog post ;^).
Thursday, December 2, 2010
USB gives a lesson in physics
With a recently bought mouse:
Googling shows affected are many, yet few good explanations are provided. This good post explains that it is indeed caused by an electrostatic discharge (ESD), which, kernel can be agreed with, may be seen as an extreme case of electo-magnetic interference (EMI).
[176149.256699] hub 3-0:1.0: port 1 disabled by hub (EMI?), re-enabling...
[176149.256706] hub 3-0:1.0: over-current change on port 1
[176149.357643] usb 3-1: USB disconnect, address 3
[176149.569692] usb 3-1: new low speed USB device using uhci_hcd and address 4
[176149.734362] usb 3-1: New USB device found, idVendor=093a, idProduct=2510
[176149.734371] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[176149.734377] usb 3-1: Product: USB OPTICAL MOUSE
Googling shows affected are many, yet few good explanations are provided. This good post explains that it is indeed caused by an electrostatic discharge (ESD), which, kernel can be agreed with, may be seen as an extreme case of electo-magnetic interference (EMI).
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