C28 SPI-A to M3 SSI3 Internal Loopback
963
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Serial Peripheral Interface (SPI)
1. Enable and configure the M3 SSI module as a SPI slave by following the steps outlined in the
Initialization and Configuration section of the
M3 Synchronous Serial Interface (SSI)
chapter.
2. Enable the corresponding loopback mode by setting SERPLOOP[SSI3TOSPIA] = 0x3 on the M3
subsystem.
3. Enable and configure the C28 SPI module as detailed in
.
To disable loopback between the M3 and C28, set SERPLOOP[SSI3TOSPIA] = 0 on the M3 subsystem.
NOTE:
Ensure that compatible CPOL and CPHA modes are used. The definition of the M3 CPOL
and CPHA bits are different from the C28 CPOL and CPHA bits. Using incompatible
configurations can cause data to be shifted by one bit.