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Question for SPI

Altera_Forum
Honored Contributor II
1,210 Views

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; 

}
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Altera_Forum
Honored Contributor II
452 Views

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.
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Altera_Forum
Honored Contributor II
452 Views

Thanks for the reply!

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