7 years, 11 months ago.

SPI slave 16bit mode setup nRF51 dk

So I'll try to keep my question short. I've included the .cpp code in this question because it's very little.

When I set up my spi I can read the data i'm sending on my tera term when i have the spi.format set to (8,2) my master is also set to mode 2 as well. But when i set my spi.format to (16,2) and program the nRF i get the the pairs of LED1-LED3 and LED2-LED4 alternately flashing with each other. I can't find what this means anywhere. Also i can't read any data on my tera term at this point as well. My master is configured as a 16 bit spi so this should work.

any help would be appreciated because I've looked everywhere and I can't figure out what is happening. Sorry I'm very new to this and excuse the formatting as well.

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include "mbed.h"

SPISlave spi(P0_25, P0_28, P0_29, P0_24); Serial pc(USBTX, USBRX);

int main() {

spi.format(16,2);

spi.frequency(100000);

pc.baud(9600);

spi.reply(0x00); Prime SPI with first reply

while(1) { if(spi.receive()) {

int v = spi.read(); Read byte from master

spi.reply(v); Make this the next reply

pc.printf("Received Data = 0x%X\n\r",v); } } }

///////////////

Question relating to:

The nRF51 Development Kit is a single-board development kit for Bluetooth Smart, ANT and 2.4GHz proprietary applications using the nRF51 Series SoC. This kit supports both development for both nRF51822 …

1 Answer

6 years, 4 months ago.

what's the use of the code given below:

spi.reply(0x00); Prime SPI with first reply

because normally spi doesn't require to give out acknowledgement (ACK) to the master , then why do we use it?