SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
Table 12-746 lists the RX FIFO trigger-level settings.
SCR[7] | TLR[7:4] | RX FIFO Trigger Level |
---|---|---|
0 | = 0x0 | Defined by the UART_FCR[7-6] RX_FIFO_TRIG bit field (8,16, 56, or 60 characters) |
0 | != 0x0 | Defined by the UART_TLR[7-4] RX_FIFO_TRIG_DMA bit field (from 4 to 60 characters with a granularity of 4 characters) |
1 | Value | Defined by the concatenated value of RX_FIFO_TRIG_DMA and RX_FIFO_TRIG (from 1 to 63 characters with a granularity of 1 character) |
Note: The combination of RX_FIFO_TRIG_DMA = 0x0 and RX_FIFO_TRIG = 0x0 (all zeros) is not supported (minimum of 1 character required). All zeros result in unpredictable behavior. |
The receive threshold is programmed using the UART_TCR[7-4] RX_FIFO_TRIG_START and UART_TCR[3-0] RX_FIFO_TRIG_HALT bit fields:
Delay = [4 + 16 × (1 + CHAR_LENGTH + Parity + Stop – 0.5)] × Baud_rate + 4 × FCLK
The RTS signal is deasserted after the UART module receives the data over RX_FIFO_TRIG_HALT. Delay means how long the UART module takes to deassert the RTS signal after reaching RX_FIFO_TRIG_HALT.