Not able to see log output in COM port for SPI.

[BeaconBLE]

Hello,

I am using NRF51 DK for developing an application. I tried running the default SPI example in the SDK 12.3 which uses the spi and spis example. The location of those examples are SDK ->examples -> peripheral -> spi & spis. When I run these examples in two different boards I can see the led blinking showing that the spi transfer is completed but when I connect my COM port to Putty software I am not seeing any output in the log. I want to connect nRF51822 boards using SPI but I cannot figure out if they are working or not without the log. If you can please let me know how do I make the log work for this specific example.

Thank You.

[Jørgen Holmefjord]

By default, the logger module is not enabled in the examples. You need to set the following define in sdk_config.h:

#define NRF_LOG_ENABLED 1

Hein said:

Not sure about the 51, but in the 52 you can not run the SPI0 and UART0 at the same time, are they both configured for instance 0 ?

This is not correct, UART does not share instance with other serial devices. Only SPI/SPIM/SPIS/TWI/TWIM/TWIS share base address.

[Jørgen Holmefjord]

Unless you are using the SD Card/FatFS library, I would recommend that you control SS pin manually, rather than modifying the driver as suggested in the link.

You cannot transmitt data from more than one device at a time on a single bus, then you need to setup multiple SPI instances. nRF51 support two SPI master instances. 

The simples solution would be to configure the transmitter as a SPI master device and the 4 others as SPI slave. You can then set SS pin manually for each device and transmitt/receive from that device. Then move to the next device.

[BeaconBLE]

So for changing the SS pin manually do I not do the changes in the nrf_drv_spi.h and nrf_drv_spi.c file and what other changes do I have to do for it to work. Also, when 4 slaves are transmitting how do I manage the timing because they cannot transmit simultaneously right. Is there a way to know whether the other slave is currently using the SPI pin or not?

Thank You.

[Jørgen Holmefjord]

Yes, no changes to the nrf_drv_spi files. You simply set and clear the SS pin in use with GPIO functions nrf_gpio_pin_set/clear(). Note that you have to setup the SS pins using nrf_gpio_cfg_output() first.

The master is always the one initiating a transfer on the SPI bus. The slaves can not start transmitting by itself. You will have full control over which slave device is transferring in the master application.

[BeaconBLE]

Hello,

I am really sorry for the trouble, I am a beginner, if you could please help me with a gist of code changes that I have to do in the SDK 12.3 spi and spis example that would be great.

Thank You.