README

This sample transfers some data bytes (128 bytes by default) via the SPI0 or
SPI1 master to a SPI slave device and displays the received bytes. See the notes
in the second part of this file, if you want to use SPI1! On the Raspberry Pi 4
there are additional SPI master devices, which can be used too. Please see the
file include/circle/spimaster.h for their pinout! You should modify the file
kernel.cpp for your needs. For a quick test you can connect GPIO9 and GPIO10
(Broadcom numbering) together. The sent data will then also be received.

The pinout of the SPI0 master is as follows:

SCLK	GPIO11
MOSI	GPIO10
MISO	GPIO9
CE0	GPIO8
CE1	GPIO7


This sample supports the SPI1 master (Auxiliary SPI master) too, which can be
used on Raspberry Pi models which have the 40 pin GPIO header. To use it, you
have to enable the #define USE_SPI_MASTER_AUX in the file kernel.h before build.
For a short test you can connect GPIO19 and GPIO20 (Broadcom numbering)
together. The sent data will then also be received.

The pinout of the SPI1 master is as follows:

SCLK	GPIO21
MOSI	GPIO20
MISO	GPIO19
CE0	GPIO18
CE1	GPIO17
CE2	GPIO16
