STM32 Primer Battery solution, Mem-cards, sound, new device?
Hello everyone,
This is my first post here. I just stumbled upon the STM32 device in an Swedish forum (as I'm swedish) and though I would read up some more on it and maybe buy one. It looks like a perfect little development board to play around with with its nice exterior!
My background is professional software engineer on the Windows platform for the last 15 years (Mainly C/C++ and C#) and a burning interest and creativity working with electronics/embedded systems in my spare time. Mostly FPGA's the last 5 years in a mix of HW&SW (Softcores like Picoblaze) but also tried out some assembler programming for hard-CPU as: Atmel Tiny13 and others. I also done some soldering and constructed my own simple extension board for
1) I read another forum post that that there are new versions coming out of the STM32 Primer with even more features , better battery charging on so on. If so, when is this due? Have the specification for this been nailed or is it still in-the-workings?
2) Have someone done a battery-mod to get the battery-thing working smoothly? IT would be nice not having the batteries fried the first time forgetting them on loading when doing lengthy debugging-hours. After reading up on it a little bit, is it easily possible to add a small circuit to control the loading AND in the doing switch to Li-Ion or Li-Po? I ask because if somebody already did this I would really like for them to share. If hard mod's like this is not supposed to spread here within the forum (for non-soldering fantasts) please post me privately.
3) Is there a way to play sound (read noise) on the device today? I read about the Buzzer, could it be used to play for example MP3/WAV-files?
3) After looking into the schematics it looks like there are unused port in the device, is that so? Are these externally ported today? Have someone tried to add a SPI-based version of a Micro-SD? Would this not be a match in heaven for this little thingy? Just think of having 4Gbyte of very cheap memory to put those pictures or MP3 into and making your Primer more of a media machine?
4) What is missing for the device to be IR-DA capable?
5) Has somebody tried to add external Joystick/Keyboard/Mouse to it?
6) I hear somebody mentioning of the MEMS being "slow" due to noise floor being high, has anyone done some modding on this to make it better? Have you tried it in the device so it actually helped?
7) I hear someone talking about adding a FRAM-circuit to it to get more RAM, has this been done in the labs at home?
OK, my expertise is lengthy and mail's filled with ideas.. I think this is enough to start with.. :-) Please answer something if you have ideas. I would really like this community to be alive if I buy one of these. And I really would like one....
Best Regards Magnus Wedmark
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2008-05-02 07:13:06STM32 Primer Battery solution, Mem-cards, sound, new device?
Re: STM32 Primer Battery solution, Mem-cards, sound, new device?
1) ... new versions ... Planned for 08Q4 3) no the buzzer is quite poor. Next versions will be much better. 4) the transmitter is not soldered (empty footprint). You have to look in the forum to find where to buy it. It will be present in the next version.
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2008-05-03 05:48:53STM32 Primer Battery solution, Mem-cards, sound, new device?
Re: STM32 Primer Battery solution, Mem-cards, sound, new device?
Francis :
1) ... new versions ... Planned for 08Q4 3) no the buzzer is quite poor. Next versions will be much better. 4) the transmitter is not soldered (empty footprint). You have to look in the forum to find where to buy it. It will be present in the next version.
OK thank you for the info, the device just look too nice to wait until Q4. I've oredered one! :-)
If somebody know anything about the other questions your're very welcome to answer.
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2008-05-19 10:03:51STM32 Primer Battery solution, Mem-cards, sound, new device?
Re: STM32 Primer Battery solution, Mem-cards, sound, new device?
A checp and simple way to implement a nagigation key would be to use an analog voltgae divider circuit, with 0-20-40-60-80-100% voltage levels for switches NOKEY/LEFT/RIGHT/UP/DOWN/ENTER
This scheme would be compatible with the current PBUTTON connection, and would not extra pins of the STM32!
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2008-05-19 12:56:40STM32 Primer Battery solution, Mem-cards, sound, new device?
Re: STM32 Primer Battery solution, Mem-cards, sound, new device?
It sounds nice. How do you implement it to optimize the number of resistors? The common point to Vcc and a resistor between each pin of the joystick and ADC_in ? And another pullup for ADC_in? Thanks.
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2008-05-21 08:54:22STM32 Primer Battery solution, Mem-cards, sound, new device?
Re: STM32 Primer Battery solution, Mem-cards, sound, new device?
Resistor Ladder Scheme looks very much like the Olimex metod on STR912 board
see center-bottom for Joystk schematics and upper right of MCU (rectangle) for where it connects (pin name/no): 5 resistors for 1 analog I/O (direction) and 2 resistors 1 digital I/O or center Enter btn.
Re: STM32 Primer Battery solution, Mem-cards, sound, new device?
yes that's right, using resistive ladders is not my invention; it's a standard way to reduce i/o pins if you have a spare ADC.
I think that the first time I read about it was many years ago in EDN or Elektor magazines.
The advatage of the series resistor approach is that you can achieve much better tolerances.
Besides, I do not understand why one would use a second i/o line for the enter key if you can chieve the same 0%-to-100% voltage swing for the enter key as suggested.
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By the way, even more extreme options exist that do not use any ADC, but use R/C timing to measure decay times. I have seen source code for the PIC to do this, but I think that such tricks are too dirty and error-prone.
