Loopback Initialization And Configuration; Ssi And Spi Connections For Loopback Mode; Loopback Modes - Texas Instruments Concerto F28M35 Series Technical Reference Manual

Table of Contents

C28 SPI-A to M3 SSI3 Internal Loopback

shows the three loopback modes available. Loopback mode is disabled by default. The

SERPLOOP register in the M3 system control register space determines the loopback mode.

Configuration of SERPLOOP is only available on the M3 master subsystem. Three different modes are

available: not connected (default), M3 SSI3 master connected to C28 SPI-A slave, and M3 SSI3 slave

connected to C28 SPI-A master. For a detailed description of the SERPLOOP register, refer to the System

control and Interrupts chapter.

SERPLOOP[SSI3TOSPIAE]

Legend: 0 = Bit cleared, 1 = Bit set, X = Any

12.2.1 Loopback Initialization and Configuration

To enable M3 SSI3 master to C28 SPI-A slave loopback mode, perform the following steps:

1. Enable and configure the M3 SSI module as a SPI master 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] = 0x2 on the M3

3. Enable and configure the C28 SPI module as detailed in

To enable M3 SSI3 slave to C28 SPI-A master loopback mode, perform the following steps:

C28 Serial Peripheral Interface (SPI)

Figure 12-12. SSI and SPI Connections for Loopback Mode

Internal Connection Logic

SERPLOOP[SSI3TOSPIAE]

Table 12-7. Loopback Modes

SERPLOOP[SSI3TOSPIAM]

C28 GPIO Mux

SERPLOOP[SSI3TOSPIAM]

SPRUH22I – April 2012 – Revised November 2019

SPIASOMI_out

SPIASIMO_out

Not Connected (default on

M3 SSI3 Master connected to

C28 SPI-A Slave

M3 SSI3 Slave connected to

C28 SPI-A Master

Submit Documentation Feedback

Table of Contents