SPRUIZ1B July 2023 – August 2024 TMS320F28P650DH , TMS320F28P650DK , TMS320F28P650SH , TMS320F28P650SK , TMS320F28P659DH-Q1 , TMS320F28P659DK-Q1 , TMS320F28P659SH-Q1
The MCAN module can be set into external loop back mode by programming MCAN_TEST.LBCK to 1. In loop back mode, the MCAN treats the transmitted messages as received messages and stores the messages (if the messages pass acceptance filtering) into an Rx Buffer or an Rx FIFO. Figure 35-10 shows the connection of the TX and RX pins to the MCAN module in external loop back mode.
This mode is provided for hardware self-test. To be independent from external stimulation, the MCAN module ignores acknowledge errors (recessive bit sampled in the acknowledge slot of a data/remote frame) in loop back mode. In this mode, the MCAN module performs an internal feedback from the Tx output to the Rx input. The actual value of the RX input pin is disregarded by the MCAN module. The transmitted messages are monitored at the TX pin.