Hello,
I have a question regarding write access to a PSRAM connected via XSPI in memory mapped mode on a STM32H7RS.
I do not completely understand if having the PSRAM memory mapped makes it available to the ECU as if it is internal RAM, meaning that it can be used to perform read and write operation of any size.
Reading some docs (e.g. the reference manual), it seems that every aspect of PSRAM management in memory mapped mode is handled automatically by the MCU configuring parameters like the CSBOUND chip select bound.
But looking at the code samples (such as this one https://github.com/STMicroelectronics/STM32CubeH7RS/blob/d06484d3e19c7d6fc963bbec5d754637f237c1ed/Projects/STM32H7S78-DK/Examples/XSPI/XSPI_PSRAM_MemoryMapped/Boot/Src/main.c#L200), it looks that the user must take into consideration aspects like page crossing and write time as indicated by the comment
/* In memory-mapped mode, not possible to check if the memory is ready
after the programming. So a delay corresponding to max page programming
time is added */
By the way CSBOUND is not configured in the example code.
Can you help me better understand which is the proper way to manage an external PSRAM and its limitation. Also, is using a RAM connected via FMC any different?
