2022-03-30 10:52 AM
2022-03-30 10:59 AM
The STM32H750VBT6 is an LQFP100 package. The LQFP100 package doesn't have the necessary pins broken out to support SDRAM. For example, FMC_A0 is missing.
Therefore, you can't use SDRAM on that chip which is why CubeMX doesn't list it as an option.
2022-03-30 11:06 AM
Thank you. I was afraid of that. This chip shortage is killing me.
I'll have to try the F series if I can get any.
2022-03-30 11:17 AM
Can external FLASH be used as a framebuffer? the VBT6 does support that.
2022-03-30 11:29 AM
2022-03-30 11:33 AM
Thanks. I'll look into that.
2022-04-09 01:39 PM
I have moved my project to the Nucleo-H7A3ZI-Q dev. board and have added the APS1604M-3SQR PSRAM chip to use as a framebuffer. I have followed the instructions in AN5050 for the OCTOSPI settings using QUADSPI. I did not see any mention of configuring the FMC so that is disabled. I added the test functions listed in AN5050 to write and read to RAM. I first run EnterQuadMode() then EnableMemMappedQuadMode() and then the test loop but it is not storing the values. If I examine the memory location 0x90000000 when the program is paused it shows all 8s and I can't manually write a value to it. I have the clock to the OCTOSPI set to 200 MHz and the clock prescaller value in the OCTOSPI parameter settings set to 3. I also added the line "PSRAM (xrw) : ORIGIN = 0x90000000, LENGTH = 2M" to the linked script. The RAM chip is soldered to a small PCB with 3" leads to the dev board and a bypass cap at the chip. Is there anything else I should be checking?
2022-04-09 01:54 PM
I did a reset to the clock configuration and set the clock for the the OCTOSPI back to 200 MHz and now I can write manually but the test program now is showing random values.