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Altera_Forum
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14 years ago

FLASH command via NIOS IO.h

Hi, I'd like to activate dynamic protection sectors ( DYB ) of a 16 bits CFI FLASH SG29GL256N, but I'm facing issues with the IOWR_16DIRECT command of the io.h : when I look the FLASH signal...
Altera_Forum's avatar
Altera_Forum
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14 years ago

IIRC the nios cpu will always do 32bit transfers to the Avalon slave, with the 4 byte enables being asserted appropriately.

For a 16bit slave there will be a 'bus width adapter' that generates two cycles with the relevant byte enables copied across - even if it means a cycle has active byte enables!

(Reads always assert all 4 byte enables.)

It might be that you are only tracing the first of the two adjacent cycles!