Hi
linked up an arduino as an SPI Slave to a BBB as master using SPI1.0.
I can get the two to communicate fine when the BBB is writing to the Arduino, however, when it reads data from the arduino it is not correctly reading what is returned. For example the Arduino is returning (as confirmed by Oscillocope on the MISO pin) a two byte stream of [0, 114], which is correct, however the BBB is only recieving [247, 247] and then [255, 255] for subsequent values. Both devices are operating in SPI mode 1.
The BBB device tree is a copy of the one posted on hipster circuits: hipstercircuits.com/enable-spi-with-device-tree-on-beaglebone-black-copy-paste/, however I notice there are other examples such as on linux.org that have the cs pin as an input, which doesn’t make sense for an SPI master.
I’m using jacek’s spi library: github.com/piranha32/IOoo/blob/master/include/SPI.h.
I’ve also got a level converter to protect the BBB from the arduino 5V. It works as advertised.
Has anyone sucessfully read data or seen the problems listed? I’ve sort of come to the end of my troubleshooting list.