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Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Nios2 SPI

Hi, I'm having some trouble reading from my IO expander with the SPI core from Altera :confused: Can anybody provide me with an example on how to issue a correct read to the spi inter...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

I ended up using the standard NIOS spi command like this:

Write : 

 
wdata = 0x40; // Write command of the chip 
wdata = 0x09; // register adr
wdata = 0x2;  // value 
alt_avalon_spi_command(SPI0_BASE, 0,
3,
wdata,
0,
rdata,
0);

Read : 

 
wdata = 0x41; // read command 
wdata = 0x12; // register adr 
ID = 0; 
alt_avalon_spi_command(SPI0_BASE, 0,
2,
wdata,
2, // reading 2 bytes 
rdata, // store bytes here 
0);

Hope this helps :)