SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
Table 24-85 lists the UART interface input/output (I/O) signals.
Signal | I/O(1) | Description | Module Level Reset Value |
---|---|---|---|
UARTi Interface Signals(2) | |||
uarti_rxd | I | Serial data input. | HiZ |
uarti_txd | O | Serial data output | 1 |
Because this pin is active high in IrDA mode and the output is muxed, this pin is set to low on reset (when the UARTi.UART_MDR1[2:0] bit field is set to 0x7) and takes the defined inactive level of that signal corresponding to when and how the UARTi.UART_MDR1 register is programmed; that is, the output is 1 (inactive for UART modem modes) and 0 (inactive for IrDA modes). | |||
uarti_ctsn | I | Clear to send | HiZ |
Active-low modem status signal. Reading the UARTi.UART_MSR[4] NCTS_STS bit checks the condition of uarti_ctsn. Reading the UARTi.UART_MSR[0] CTS_STS bit checks a change of state of uarti_ctsn since the last read of the modem status register. The auto-CTS mode uses uarti_ctsn to control the transmitter. | |||
uarti_rtsn | O | Request to send | 1 |
When active (low), the module is ready to receive data. Setting the UARTi.UART_MCR[1] RTS bit activates uarti_rtsn, which becomes inactive as the result of a module reset, loopback mode, or clearing the UARTi.UART_MCR[1] RTS bit. In auto-RTS mode, uarti_rtsn becomes inactive as a result of the receiver threshold logic. | |||
UART1 Modem Signals | |||
uart1_dcdn | I | Data Carrier Detect | HiZ |
Active-low modem status signal. The condition of uart1_dcdn can be checked by reading UART_MSR[7] NCD_STS register bit. Any change in its state can be detected by reading UART_MSR[3] DCD_STS bit. | |||
uart1_dsrn | I | Data Set Ready | HiZ |
Active-low modem status signal. Reading UART_MSR[5] NDSR_STS register bit checks the condition of uart1_dsrn. Reading UART_MSR[1] DSR_STS bit checks a change of state of uart1_dsrn since the last read of the UART_MSR register. | |||
uart1_dtrn | O | Data Terminal Ready | 1 |
When active (low), this signal informs the modem that the module is ready to communicate. It is activated by setting UART_MCR[0] DTR register bit. | |||
uart1_rin | I | Ring Indicator | HiZ |
Active-low modem status signal. The condition of uart1_rin can be checked by reading UART_MSR[6] NRI_STS register bit. Any change in its state can be detected by reading UART_MSR[2] RI_STS bit. |
The path from a module pin to device pad(s) is defined at the device I/O logic level. The I/O logic maps the module signals to the different pads of the device and is programmable in the Control Module registers. For more information on control module settings, see Pad Configuration Registers, in Control Module.