RE: Why does nRF51822 spi_master.c have timeout code?

Paolo D — Thu, 08 May 2014 16:39:57 GMT

There is a bug in this driver which causes problems when using it with two SPI modules simultaneously. The variable 'SPI' which is global should instead be local to each function which uses it. Otherwise a function could set the variable and be interrupted by a function which tries to use the other SPI peripheral, overwriting the variable and causing the wrong peripheral to be used.

RE: Why does nRF51822 spi_master.c have timeout code?

ovrebekk — Tue, 11 Feb 2014 16:39:25 GMT

Hi Philip

The SPI driver in the SDK is quite old, and was written for a very early revision of the nRF51822 chip. Back then the SPI hardware was less reliable, and the time out mechanism was put in place in case of HW issues.

You are correct that this is not really needed any more, as there are no known issues with the current SPI implementation.

For an example of an SPI driver without any timeout code, please have a look at the attached example. It is quick enough to write and read data back to back at 2 MHz (though there are some microseconds of delay before and after a transaction).

Best regards Torbjørn

SPI master example.zip