SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
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 26-113).
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) |