Memory requirements for STM32H743XI EVAL board.

[BBV]

Hi All,

I'm trying to implement the eval board for a project seems like they have used a lot of different types of memory from HW perspective. I wanted to know what memory is being used for what purpose for this specific board so that I can change it if required. If you can please point to the firmware perspective of the memory use for this particular eval board it would be helpful.

Thanks.

[Tesla DeLorean]

The demo uses the QSPI for bitmap/image data as I recall

STM32Cube_FW_H7_V1.3.0\Projects\STM32H743I_EVAL\Demonstration\STemWin\SW4STM32\STM32H743I_EVAL\STM32H743XIHx_FLASH.ld

The parallel NOR isn't used, but could be if you have a specific purpose for it, like a kernel or file system image.

Generally your choice is driven by speed, bandwidth, size, etc.

8Mx32-bit SDRAM, 1Mx16bit SRAM and 8Mx16-bit NOR Flash

1x 1-Gbit Twin Quad-SPI NOR Flash memory or 2x 512Mb Quad-SPI NOR Flash

[BBV]

Thank you Clive. I would be using external SDRAM for the first time hence had a question. Here on this eval board SDRAM, SRAM and NOR Flash have been connected to total of 53 GPIO pins. And for my design implementation I really need 33 GPIO pins. I removed audio chip and now I have total of 11 which I can use. But I am still falling short of GPIO's.

My question is can I use these parallel interface GPIO's as dual function? One for memory and another for suppose input to gate to turn the led on and off. If so whats the best possible way to do it.

I can certainly use one more MFX on the board but the delay would kick in. Hence the question.

Your input would be helpful. Thank you.

[Tesla DeLorean]

If you just need a lot of outputs consider some latches decoded on the FMC.

Memory interfaces use a lot of pins to achieve high speeds. You could half the data bus from 32 to 16-bit but the potential bandwidth also halves, which will be an issue for video application where size and refresh rates define expectations.​

[BBV]

Thank you for the reply. So for the project the LCD just needs to display images or frames with different data written on it and no video. So certainly I can consider halving the data bus to 16-bit. But I would want to have option of 32bit bus for the first prototype and GPIO's too.

Can you please elaborate this "If you just need a lot of outputs consider some latches decoded on the FMC."

Thank you.

[Tesla DeLorean]

I'm talking basic micro-controller interfacing, in old days you'd use a 74LS273 latched with address and chip select logic, today people use CPLD or FPGA to do equivalent tasks as it reduces bus loading, and a lot of glue logic.

Consider shift registers where you shift and latch however long of a bit stream you want to manage, with 3 pins.

People have IC's to do LED and switch matrix stuff, those I think can be daisy-chained relatively easily.

I'd push low bandwidth stuff off chip to a slave device, perhaps a large pin count CM0 device.

[BBV]

Ok got it thank you.