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Altera_Forum's avatar
Altera_Forum
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19 years ago

SPI RX problems

Hi I am trying to receive data via SPI on the Nios II using a Cyclone II. The Nios is the slave and the SPI master transmits data at 2MHz. I have tested transmitting data from the Nios ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
19 years ago

There were 2 problems:

1.) The IF statement was wrong... (stupid mistake)

2.) Clearing the Status Register every time erased some of the RRDY bits.

Here is the working test code:

while (1){

if (IORD_ALTERA_AVALON_SPI_STATUS(SPI_0_BASE) &

ALTERA_AVALON_SPI_STATUS_RRDY_MSK){

//read the byte and print it to screen

printf("%02x\n", (IORD_ALTERA_AVALON_SPI_RXDATA(SPI_0_BASE) & 0x0FF));

//clears the status register

IOWR_ALTERA_AVALON_SPI_STATUS(SPI_0_BASE, 0);

}

}