SPRUHZ7K August 2015 – April 2024 AM5706 , AM5708 , AM5716 , AM5718 , AM5718-HIREL
Software flow control is enabled through the enhanced feature register (UARTi.UART_EFR) and the modem control register (UARTi.UART_MCR). Different combinations of software flow control can be enabled by setting different combinations of the UARTi.UART_EFR[3:0] bit field (see Table 24-113).
Two other enhanced features relate to software flow control:
The XON-any character is written into the RX FIFO even if it is a software flow character.
| Bit 3 | Bit 2 | Bit 1 | Bit 0 | TX, RX Software Flow Controls |
|---|---|---|---|---|
| 0 | 0 | X | X | No transmit flow control |
| 1 | 0 | X | X | Transmit XON1, XOFF1 |
| 0 | 1 | X | X | Transmit XON2, XOFF2 |
| 1 | 1 | X | X | Transmit XON1, XON2: XOFF1, XOFF2(1) |
| X | X | 0 | 0 | No receive flow control |
| X | X | 1 | 0 | Receiver compares XON1, XOFF1 |
| X | X | 0 | 1 | Receiver compares XON2, XOFF2 |
| X | X | 1 | 1 | Receiver compares XON1, XON2: XOFF1, XOFF2(1) |