F28M35H52C: C28 writes to the EPI0 extended RAM

Cherry,

   Would you be able to share the schematics privately?

Hi Hareesh,

Schematic: a RAM (CS0) and a flash (CS2) are expanded out of EPI0, same as the example of spruh22i.pdf:

This issue is discussed in 17.9.2 Memory Protection for spruh22i.pdf, which by default is capable of reading and writing EPI0 extended external RAM, and the value in 0x400F-B938 is 0 and should be writable.

Thanks and regards,

Cherry

If you scope the read pin, do you see a low-going pulse?

Hi,

The case is they can read but cannot write.

Read pin and write pin have low-going pulses and working fine when the M3 reads and writes to RAM. Read pin has a low-going pulse when C28 reading RAM. Write pin has no low-going pulses when C28 writing RAM and is not able to write.

Thanks and regards,

Cherry

I need some time to research this. I will get back to you in a day or two.

Hi,

May I know is there any update on this?

Thanks and regards,

Cherry

Cherry,

   Apologize for the delay. Will reach out to you offline.