Loopback Initialization And Configuration; Uart And Sci Connections For Loopback Mode - Texas Instruments Concerto F28M36 Series Technical Reference Manual

C28 SCI-A to M3 UART4 Internal Loopback
Figure 13-11 illustrates the loopback connections between the C28 SCI-A and M3 UART4. The C28 SCI-
ATx is connected to the M3 UART4Rx and C28 SCI-ARx is connected to M3 UART4Tx when loopback
mode is enabled. Loopback is enabled by setting the UART4TOSCIA bit in the M3 SERPLOOP register.
For a complete description of the SERPLOOP register, refer to the System Control and Interrupt chapter.
Figure 13-11. UART and SCI Connections for Loopback Mode

13.2.1 Loopback Initialization and Configuration

To enable M3 UART4 to C28 SCI-A loopback, follow these steps:
1. Enable and configure the M3 UART4 module by following the steps outlined in the Initialization and
Configuration section of the M3 Universal Asynchronous Receivers/Transmitters (UARTs) chapter.
2. Enable internal loopback mode by setting SERPLOOP[UART4TOSCIA] = 1 on the M3 subsystem.
3. Enable and configure the C28 SCI-A module as described in
To disable loopback between the M3 and C28, set SERPLOOP[UART4TOSCIA] = 0.
1030
C28 Serial Communications Interface (SCI)
M3 GPIO Mux
0
Rx
1
Tx
SERPLOOP[UART4TOSCIA]
Copyright © 2012–2019, Texas Instruments Incorporated
C28 GPIO Mux
Tx
0
Rx
1
Section 13.1.
SPRUHE8E – October 2012 – Revised November 2019
www.ti.com
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