Development Board

[Tectu]

What do you guys think of such a development board? Would you like to see some other features?

• STM32F407ZGT
• On-Board programmer & debugger
• external SRAM (0 to 8MBit)
• microSD card slot (SDIO)
• USB-OTG
• 3-Axis Accelerometer
• 10/100 T-Base Ethernet (no PoE)
• Audio in- and output (3.5mm jack)
• 5", 800 x 480 TFT touchscreen (resistive)
• UEXT connectors
• Various other expension connectors (CAN, RS232, ...)

~ Tectu

[barthess]

what about small DCMI camera?

[mobyfab]

Some stuff could be changed to make this more interesting/powerful. (but price will go up a bit)

• STM32F439BI
• 256 Mbit Sdram (32MB) or more to run code from it (copy from sd card to sdram)
• On-board debugger and/or connector for stlink
• Same TFT but via direct drive from STM32
• 5F SuperCap on VBAT
• Amplified audio codec on I2S, or mini class D amplifier (such as ST's TS2012) on DAC output
• A bunch of tactile switches
• A bunch of small npn transistors to drive things like leds/buzzers

Everything else is nice.

That gives enough capacities to experiment pretty much anything.

[Tectu]

Is the STM32F439 yet available? The SDRAM does also just work with the new F42x F43x. The current F40x is not capable of using SDRAM at all. The SDRAM would indeed be nice since it's way cheaper and faster, as well as available in higher capacities as you mentioned correctly.
The same with the TFT, this only works when the new F4 are available and as far as I am informed there are no release dates available at all.

About the programmer: It could be made with both options, shouldn't hurt at all.
About the audio: I thought some CS4344-CZZ would do the trick, together with some OpAmp magic in the back, maybe.
About the exentions: I would rater use real opto-copplers then. Seems to be the safer option for a dev board.

However, the price is hot... With the specs I posted above the board will be around 150$ in material prices. Not sure if anyone is able to afford it.

About the camera: Nice option, should definitely be considered.


~ Tectu

[skute]

I have used dev boards from http://www.wvshare.com/column/STM32_Dev ... tBoard.htm. The main boards are inexpensive and once you buy a "package" the peripherals are interchangeable.

[inmarket]

Keep it simple initially with the good expansion options. You can always do a more expensive board later. The key is getting something out there to start with.
My suggestions...
CPU
Ethernet
USB OTG
JTAG
UEXT
Optional RAM and/or Flash
Access to all other IO pins
Perhaps a small prototyping area

With the right connector you could add an IO board containing say...
A joystick 5 way switch
A couple of push-buttons
A couple of toggle-buttons
A couple of trimpots (analogue dials)
3 or 4 leds

Another add-on board:
CS4344 (or similar) audio codec

Another add-on board:
LCD + Touch

Another add-on board:
SDCard slot

Another add-on board:
RS232

Using this approach keeps the initial board cheap and simple with most of the complexity ensuring the IO connectors are right for the add-on boards. Stackable would be nice but not essential unless IO for the above overlaps.

[Tectu]

I totally understand your point, but then we don't have to do a board our self. There are plenty of these "split apart" solutions available and they are mostly pretty annyoing and don't make the entire thing less expensive at all. The idea is to create a board where everyone has the same - maybe some options which are not already soldered like ethernet or audio, but the actual board is the same to keep development uniform. And when it comes to speed, making expansion boards and expansion interfaces with cables and everything seems so be not a good solution, especially when dealing with interfaces like FSMC for external memory or a TFT.


~ Tectu

[inmarket]

In that case - all of the above functions except the RS232 (not much use these days).

I agree cables are a pain and not good for fast signal integrity although pin header arrangements are better.

[Giovanni]

I would make a board good for testing, so put there some I2C peripherals, some SPI peripherals, something requiring ICU, PWM etc.

But I agree with inmarket that would be a good idea to not make it too complex, the Olimex STM32-P407 is a board that wanted to do everything and I ultimately never use it, i prefer the almost naked STM32-P407 and the discovery kits.

An alternate idea would be to make a board with the STM32F30x, it is much more modern and we could target it to implement a low cost hobby instrument (digital analyzer, oscilloscope, signal generation, SPI/I2C monitor) so:
- Two protected analog inputs with connectors.
- Two analog outputs connected to the DACs for signal generation.
- USB connector.
- Some LEDs and buttons.
- SPI LCD with touch interface.
- I2C storage like M24M01.
- 8/16 protected digital inputs/outputs with I2C and SPI.
- 20 pins connector with lots of I/O and power.

The on-board debugger would be nice too.

BTW, I am thinking to the F3 because its high performance ADCs and improved I2C,SPI,USARTs.

Giovanni

[Tectu]

I can just agree with the P407. The board seemed to be a good choice but it really is a pain.
My original plan was to build a board which is the exact same size as the TFT panel to create a tablet-like configuration (of course the TFT would be optional). I guess this is then not the way the community would like to go?


~ Tectu