SPI hangs waiting for EVENTS_READY

[Tomas]

Hi,

I'm trying to get SPI (master) to work (nRF51822) for communicating with a quadrature counter (LS7366R). I've read several implementations of SPI master, such as the one in RFduino and the mbed library, and I've read the reference manual.

After a few bytes of exchange, the communication hangs waiting for EVENTS_READY to turn 1. See the while loop below in my code. Sometimes it happens on the first byte, and sometimes after a few more. The data I get back is all 0xFF, which isn't correct, but that might be unrelated.

Here's the code. device->module is set to NRF_SPI0.

uint8_t tfspi_transmit(tfspi_device_t *device, uint8_t byte) {
device->module->TXD = byte;
while (device->module->EVENTS_READY == 0); // Infinite loop here
device->module->EVENTS_READY = 0;
uint8_t readByte = device->module->RXD;
return readByte;

}

Maybe this is something someone has seen before? Thanks for your help!

[Dan Danknick]

Did you clear the Slave Select pin before transmitting? Is the SPI_MODE correct? There is a lot of setup code you are not providing to help us help you.

But most importantly: is there a reason you're not just using the Nordic-provided spi_master_mod.c ? It has worked fine for me communicating with two different peripherals.

Dan

[Tomas]

Any idea where I can get spi_master_mod.c? Googling doesn't yield much. Thanks!

[Tomas]

Turns out it wasn't code-related at all. The GND pin on my dev board was apparently not actually connected to ground until a jumper was soldered. So after correctly applying ground to my SPI slave, things work fine. Not sure why this hung EVENTS_READY. :)

[Ck]

For me it's working ok since I'm not using WFE. But with WFE it'll stuck in infinite loop, looks like no system event is generated, just a flag is set:

while (device->module->EVENTS_READY == 0) __WFE(); // Infinite loop here

[Petter Myhre]

Thank you for answering your own question.