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SPI problems :)
Topic last updated 06 Nov 2010, by 
Ian Molesworth.
2
replies
Ian Molesworth.
2
replies
i am buzy with the MBED and a omneo Q5 PRAM device, to say it easy its a kind of flash memory.
to start i begin with sending a Read identification command so it sends some data back, manufactory, data type and memory amouth.
the command is 0x9F, it should return 0x20, 0xDA, 0x18.
to make stuff easy i first bitbanged it, worked perfecty, code here:
http://pastebin.com/v90qJb16
first 8 bits to send the 9F command, then 24 low bits to recieve data.
but bitbanging is nice as a test but absolutly not acceptable for normal applications.
so over to SPI, i used this code:
http://pastebin.com/JmSx8YCm
and it doesnt work, the clock line is doing funny :o
http://oi55.tinypic.com/dq0wv8.jpg
first the CS line goes low like it should but at the same time the CLOCK goes low to, and then high and while doing that it clocks the first bit in wrong.
ok, lets try it again, SPI was in mode 3 first, now mode 0
and now it pauzes after every byte, why?
i get some data back but not the right data as you can see.
can someone help me to get this device working properly?
datahseet is here
http://www.numonyx.com/Documents/Datasheets/210052_P5Q_DS.pdf
on page 26 is the timing diagram for the Read Identification command.
Rik