2022-06-09 06:45 AM
For the STM32F429ZIT Discover Board, need information and URL links about GPIO pins expansion hardware and C++ Mbed programming examples for using the expanded pins please?
Thanks,
2022-06-09 06:56 AM
Kind of recall that detail being in the User Manual, and also in the Schematics, see "CAD Resources" tab on the related product pages.
The STM32F429I-DISCO being a particularly bad design example because nearly all the pins are used by the SDRAM and LCD, to the exclusion of ETHERNET, SDIO, CAN, etc.
Only a handful of pins available for GPIO or ADC inputs.
This really isn't an MBED or ARDUINO centric venue, the SPL and HAL (CubeF4) both should have examples for this board in their related packages.
2022-06-09 07:04 AM
@Community member In my opinion, it is mean to speak of a "bad design", which is why I have to disagree here: DISCOVERY boards are not tools for practical use, but are intended as evaluation tools with which the capabilities and functions of the respective STM32 can be evaluated. For universal development with extensive freedom in the use of the GPIOs, the NUCLEO boards were created.
But I completely agree with your other statements.
Regards
/Peter
2022-06-09 07:17 AM
The 'F429 Disco at least has many if not most of the chip's pins brought out, so if you don't want to use DRAM and/or LCD, you can simply keep their chipselects inactive and the pins then are essentially available for experimentation.
The LCD is also usable in SPI mode, freeing up the RGB interface pins.
This is in contrast to *all* Discos newer than the 'F429, which are esentially unusable except for the onboard peripherals and very few "arduino" pins.
JW
2022-06-09 07:20 AM
Many thanks to both Tesla and Peter for the excellent information.
I have both Nucleo-F429ZI and STM32F429I-DISC1 boards.
For the discover board I have following link with information about various pins:
https://os.mbed.com/platforms/ST-Discovery-F429ZI/#board-pinout
Is there a similar URL link for the Nucleo board please?
Is there a URL link, that tells about how many available GPIO pins Nucleo board has and what are their pin #s ?
Any URL links to information about, how can we expand to more GPIO pins please?
Thanks and best regards,
2022-06-09 07:30 AM
Well, not in the shiny colourful way that mbed.com presents it, but in great detail in the tab CAD Resources that @Community member already mentioned. There you'll find GERBER and schematics.
Together with the data sheet of the STM32F429 and the reference manual RM0090, you have all the information about which pins can be used.
Does it answer your question?
Regards
/Peter
2022-06-09 07:45 AM
Perhaps, but in order to learn from failure, you also have to recognize failure, and avoid it.
Most of the DISCO and NUCLEO boards are very good, the adoption of the Arduino shield has helped focus design goals. Both the DISCO and EVAL boards tend to be very pin constrained, and this is compounded by the inflexibility of the pin muxing options. Now I understand why you don't want to have to route high speed signals all over the die and pad-ring, but when you're left with NO OPTIONS, it does suggest that those in the design meeting(s) didn't advocate sufficiently for usability. And this gets to be particularly telling in low-pin count offerings. And for things like the F429-DISCO where there's very limited option for any expansion or usage beyond "here's a cheap board with a good screen and lots of memory", but has poor connectivity options.
The STM32F429I-DISCO is however the most broken design ST has delivered, at least in its ability to expose usable pins. I think introspection on this, and warning people away and to better choices, is the most prudent path. I also find that straight-forward communication saves everybody time. And while at times this can be indelicate, it does need to be done in order for things to change.
I will also note that many of the EVAL/DISCO boards use parts which are denser than most people are comfortable with manufacturing with, on boards of complexity/cost that most cannot accommodate.
2022-06-09 07:47 AM
Shiny and colorful Nucleo-F429ZI pinout:
https://os.mbed.com/platforms/ST-Nucleo-F429ZI/
I still don't understand what is the question.
JW
2022-06-09 07:56 AM
I2C IO-Expanders, or ST's MFX strategy used on several of the high density boards is an option.
2022-06-09 08:02 AM
Hello JW, thank you very much for the excellent information about feature to not use DRAM and/or LCD.
I do not need to use DRAM and/or LCD display.
Are there any URL links that have detailed steps/information for disabling DRAM/LCD please?
Thanks,