Hi,

I am programming the flash memory of an AT91SAM7S256 via the SAM-BA protocol.
Then, to verify that the flashing is OK, I start reading the flash-memory immediately after the writing completes.
I'm using the the command R00100000,100# which reads the first flash page.

The first 49 to 52 bytes (it's somewhat random) tend to be zero. Reading the page a second time works.

So how do I write the flash pages?
I wait for the FRDY bit of the EFC Status register to become true. Then I write the 256 bytes to 0x00100000. Then I write the write command to write the first page into the EFC Command register, and then I wait for the FRDY bit again.

Reading the page after that seems to fail horribly. Is there some other thing that I need to do after writing a flash page?
Is there some other flag in some other register that I'd need to wait for?

It seems that I have similar problem. I am now testing AT91SAM7S512 and want to use second bank (EFC1 - the upper 256KB half) as data flash (cyclic buffer for events, partial page writes).

I have found that I read zeros after writing a page and waiting for FRDY bit. BUT:

WHEN I PERFORM A FETCH (READ) OF THE FLASH AFTER LAST WRITE (TO WRITE ONLY LATCH BUFFER) AND BEFORE WRITING TO MODE (NOERASE BIT) AND COMMAND REGISTERS, IT WORKS.

I have also found a code from previous programmer - flash programming in boot used for firmware update on AT91SAM7S256 - that checked first word in memory - read before page write command, wait to have its value (reset vector) after FRDY set and wait another 2ms. It seemed a nonsence at first look, but now I think he encountered the same problem as I do now.