SPI read and write single bytes with delays

RE: SPI read and write single bytes with delays

Jørgen Holmefjord — Tue, 12 Feb 2019 08:38:08 GMT

Please check if you are affected by errata 58.

RE: SPI read and write single bytes with delays

Bernard Chan Lye Hock — Tue, 12 Feb 2019 00:43:30 GMT

I tried this idea and it is working for me. However, I find from the scope that in the SPI_Read it would transfer 16 bits of data instead of 8 bit read data. Do you see this as well?

RE: SPI read and write single bytes with delays

Jørgen Holmefjord — Thu, 26 Jul 2018 15:51:15 GMT

This is in line with the documentation:

The SPI master is a synchronous interface, and for every byte that is sent, a different byte will be received at the same time; this is illustrated in Figure 3.

RE: SPI read and write single bytes with delays

mmmark84 — Tue, 24 Jul 2018 14:16:12 GMT

Seems calling nrf_drv_spi_transfer(&spi0, &tx, 0, &rx, 1); did the trick!

void SPI_Write(unsigned char spibus, unsigned char device, unsigned char byte)
{
	if (spibus == SPI0_BUS)
	{	
		#ifndef BLOCKING_MODE
			spi0_xfer_done   = false;
		#endif
		nrf_drv_spi_transfer(&spi0, &byte, 1, NULL, 0);
		#ifndef BLOCKING_MODE
			while(spi0_xfer_done == false) {}
		#endif
	}
}


unsigned char SPI_Read(unsigned char spibus, unsigned char device)
{
	char data;
	data = 0x00;
	if (spibus == SPI0_BUS)
	{	unsigned char tx = 0xFF;
		unsigned char rx = 0xFF;
		#ifndef BLOCKING_MODE
			spi0_xfer_done   = false;
		#endif
		nrf_drv_spi_transfer(&spi0, &tx, 0, &rx, 1); // 1 dummy byte sturen			
		#ifndef BLOCKING_MODE
			while(spi0_xfer_done == false) {}
		#endif
		return rx; 
	}
	return (data); 
}