Figure 677. Rx Lvds Loopback Mode - STMicroelectronics SPC572L series Reference Manual

LVDS Fast Asynchronous Serial Transmission (LFAST) – Interprocessor Communications
RXDATA_P
LR
RXDATA_N
TMCR[LPMOD] = RX LVDS LOOPBACK
TXDATA_P
LD
TXDATA_N
Entry to Rx LVDS Loopback mode:
1. S/W programs TMCR[LPMOD] = 001b.
2. Loopback can be turned ON by either of the following methods:
–
–
Exit from Rx LVDS Loopback mode can be done by any of the following methods:
•
S/W programs TMCR[LPON] = 0.
•
For LFAST Slave:
–
47.7.7.1.3 Tx loopback mode without automatic frame generation
This loopback mode is provided to verify the LFAST functionality, if LVDS pads are not
functional. In this loopback mode the data transmitted by LFAST on Tx LVDS output is
loopbacked internally on Rx LVDS input, bypassing LVDS pads.
1278/2058

Figure 677. Rx LVDS LoopBack mode

S/W writes TMCR[LPON] = 1.
For Slave Only: - Reception of ICLC Frame with Payload = FFh (Loopback mode
ON), from LFAST Master.
Transmission of ICLC frame with payload 38h (Test mode off), from LFAST
Master.
DocID027809 Rev 4
Rx CONTROLLER
Tx CONTROLLER
CSR
RX FIFO
CSR
TX FIFO