Question for SPI

Altera_Forum · ‎07-07-2017

Hello! Please tell me how to check the status of the pin MISO.

unsigned long int Get7794_Data(alt_u8 channel)

{

unsigned long int data;

alt_u8 cfg_reg;

cfg_reg = (channel-1)&0xFF;

spi_select_slave(0x21000,0);

spi_send(0x21000,0x10);

spi_send(0x21000,0x00);

spi_send(0x21000,cfg_reg);

//----------------

// ????????? DOUT/RDY - the line goes low when a new data-word is available in the output register

//----------------

spi_send(0x21000,0x58);

data = (unsigned)(spi_send(0x21000,0x58)) << 16;

data |= (unsigned)(spi_send(0x21000,0x58)) << 8;

data |= (unsigned)(spi_send(0x21000,0x00));

spi_deselect_slave(0x21000,0);

return data;

}

Altera_Forum · ‎07-08-2017

One way is to add a PIO peripheral with an input connected to the MISO pin and monitor that directly.

The code you pasted is just showing (normal) byte-wise access of the peripheral so there is no direct way to poll the MISO pin status.

Altera_Forum · ‎07-08-2017

Thanks for the reply!