I am using the MPC5566EVB. I am trying to write and read from the external SRAM chip on the board. I have a Oscope connected to the CS(CS0) line for the SRAM Chip. I can see a chip select each time I write to the SRAM. When reading from the SRAM the CS line is not selected on every read. It seems to be sporadically toggling CS on reads from the external SRAM. Does anyone know what could be causing this? Is there something I am not understanding about reading and writing from external memory? Let me know if you need anymore information.
Thanks,
Matt
Solved! Go to Solution.
The problem turned out to be CACHE. The external SRAM section was being cached. When I marked the section as cach inhibited, each time I read the external memory, I could see the CS line being toggled.
The problem turned out to be CACHE. The external SRAM section was being cached. When I marked the section as cach inhibited, each time I read the external memory, I could see the CS line being toggled.