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Altera_Forum's avatar
Altera_Forum
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8 years ago

Signal Tap II reading a "1" from SO of FLASH CHIP always, without changes. why?

I'm creating a very simple Flash controller as a school project. The flash chip is MX25L3206E and the FPGA is 5CEFA4F23C8. I created the code attached and routed the proper pins from the chip. After ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
8 years ago

The subtle part of the datasheet you're missing is the phrase

--- Quote Start ---

The Page Program (PP) instruction is for programming the memory to be "0".

--- Quote End ---

The PP command will only allow you to change the state of any given bit from a 1 to a zero. To change it back to a 1 you need to issue a sector/page/device erase command.

You can continue to issue PP commands, and they will 'work', providing you're only ever writing more zeros to the device than are currently in there.

Cheers,

Alex