Nios2 SPI

Altera_Forum · ‎06-09-2010

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 interface with the 'alt_avalon_spi_command' ??

Thanks :)

-mitch

Altera_Forum · ‎06-09-2010

I use something like that

 IOWR(SPI_CYCLONE3_BASE, ALTERA_AVALON_SPI_TXDATA_REG, tosend);
    while (!(IORD(SPI_CYCLONE3_BASE, ALTERA_AVALON_SPI_STATUS_REG) &  0x0020));
    return IORD(SPI_CYCLONE3_BASE, ALTERA_AVALON_SPI_RXDATA_REG);

Altera_Forum · ‎06-09-2010

could you show me the your complete code for your spi interface?

Altera_Forum · ‎06-09-2010

I send 16bits. 1 read/write bit, 7 address bits and 8 datas bits.

void  WriteReg(alt_u8 adress, alt_u8 m_data)
{
    alt_u16 tosend;
    tosend = 0x8000 | ((adress << 8) & 0x7F00) | (m_data & 0x00FF);
    IOWR(SPI_CYCLONE3_BASE, ALTERA_AVALON_SPI_TXDATA_REG, tosend);
    while (!(IORD(SPI_CYCLONE3_BASE, ALTERA_AVALON_SPI_STATUS_REG) & 0x0020));
}
alt_u8  ReadReg(alt_u8 adress)
{
    alt_u16 tosend;
    tosend = (adress << 8) & 0x7F00;
    IOWR(SPI_CYCLONE3_BASE, ALTERA_AVALON_SPI_TXDATA_REG, tosend);
    while (!(IORD(SPI_CYCLONE3_BASE, ALTERA_AVALON_SPI_STATUS_REG) & 0x0020));
    return IORD(SPI_CYCLONE3_BASE, ALTERA_AVALON_SPI_RXDATA_REG);
}

Altera_Forum · ‎06-23-2010

Hi

I have the similar problem-i can write to the register, but when i try to read from register, i dont became anything, all signals-CS, CLK, MISO are 0...

alt_spi_command run also, but only when i write to register...

can anybody help me, any suggestion?

Altera_Forum · ‎06-24-2010

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 :)

Altera_Forum · ‎10-20-2010

and how would that work without the standard command?

I'm an altera newbee and have the same problem.

i need to send 7 bit reg-addr.+1bit r/w and 16 bit data

I'm trying with

 
#include
<altera_avalon_spi_regs.h>
#include <altera_avalon_spi.h>
 
 
main{
int test;
 
while (!(IORD_ALTERA_AVALON_SPI_STATUS(SPI_BASE) & ALTERA_AVALON_SPI_STATUS_TRDY_MSK));
 
IOWR_ALTERA_AVALON_SPI_TXDATA(SPI_BASE, 0xFFFF);
 
while (!(IORD_ALTERA_AVALON_SPI_STATUS(SPI_BASE) & ALTERA_AVALON_SPI_STATUS_TRDY_MSK));
 
test=IORD_ALTERA_AVALON_SPI_RXDATA(SPI_BASE);
 
 
 
 
}

but the thinks i write dont match with the read data... :(

Any help?

Altera_Forum · ‎01-20-2014

what pins did you assign your MISO,MOSI,SS,SCK ??