Add line control (DTR/DSR)

DSR doesn't do anything yet.

CMakeLists.txt

@@ -25,4 +25,8 @@ if(FLOW_CONTROL)
 target_compile_definitions(uart_bridge PUBLIC FLOW_CONTROL=1)
 endif()
 
+if(LINE_CONTROL)
+target_compile_definitions(uart_bridge PUBLIC LINE_CONTROL=1)
+endif()
+
 pico_add_extra_outputs(uart_bridge)

README.md

@@ -11,23 +11,45 @@ This software is provided without warranty, according to the MIT License, and sh
 Raspberry Pi Pico Pinout
 ------------------------
 
+UART0:
 | Raspberry Pi Pico GPIO | Function  |
 |:----------------------:|:---------:|
-| GPIO0 (Pin 1)          | UART0 TX  |
+| GPIO0 (Pin 1)          | TX        |
-| GPIO1 (Pin 2)          | UART0 RX  |
+| GPIO1 (Pin 2)          | RX        |
-| GPIO2 (Pin 4)          | UART0 CTS |
+| GPIO2 (Pin 4)          | CTS       |
-| GPIO3 (Pin 5)          | UART0 RTS |
+| GPIO3 (Pin 5)          | RTS       |
-| GPIO4 (Pin 6)          | UART1 TX  |
+| GPIO4 (Pin 6)          | DTR       |
-| GPIO5 (Pin 7)          | UART1 RX  |
+| GPIO5 (Pin 7)          | DSR       |
-| GPIO6 (Pin 9)          | UART1 CTS |
-| GPIO7 (Pin 10)         | UART1 RTS |
 
-Optional Hardware Flow-control
+UART1:
+| Raspberry Pi Pico GPIO | Function  |
+|:----------------------:|:---------:|
+| GPIO8  (Pin 11)        | TX        |
+| GPIO9  (Pin 12)        | RX        |
+| GPIO10 (Pin 14)        | CTS       |
+| GPIO11 (Pin 15)        | RTS       |
+| GPIO12 (Pin 16)        | DTR       |
+| GPIO13 (Pin 17)        | DSR       |
+
+Optional Hardware Flow and Line control
 ------------------------------
 
-Hardware Flow-control is disabled by default, but can be compiled in by running:
+Hardware Flow-control (RTS/CTS) is disabled by default, but can be compiled in by running:
 
 ``` bash
 cmake -DFLOW_CONTROL .
 make
 ```
+
+Line control (DTR/DSR) is disabled by default, but can be compiled in by running:
+
+``` bash
+cmake -DLINE_CONTROL .
+make
+```
+
+To enable both:
+``` bash
+cmake -DLINE_CONTROL -DFLOW_CONTROL .
+make
+```

uart-bridge.c

@@ -32,6 +32,10 @@ typedef struct {
 	uint8_t rts_pin;
 	uint8_t cts_pin;
 #endif
+#ifdef LINE_CONTROL
+	uint8_t dtr_pin;
+	uint8_t dsr_pin;
+#endif
 } uart_id_t;
 
 typedef struct {
@@ -54,14 +58,22 @@ const uart_id_t UART_ID[CFG_TUD_CDC] = {
 #ifdef FLOW_CONTROL
 		.cts_pin = 2,
 		.rts_pin = 3,
+#endif
+#ifdef LINE_CONTROL
+		.dtr_pin = 4,
+		.dsr_pin = 5,
 #endif
 	}, {
 		.inst = uart1,
-		.tx_pin = 4,
+		.tx_pin = 8,
-		.rx_pin = 5,
+		.rx_pin = 9,
 #ifdef FLOW_CONTROL
-		.cts_pin = 6,
+		.cts_pin = 10,
-		.rts_pin = 7,
+		.rts_pin = 11,
+#endif
+#ifdef LINE_CONTROL
+		.dtr_pin = 12,
+		.dsr_pin = 13,
 #endif
 	}
 };
@@ -250,6 +262,13 @@ void init_uart_data(uint8_t itf) {
 	gpio_set_function(ui->cts_pin, GPIO_FUNC_UART);
 #endif
 
+#ifdef LINE_CONTROL
+	gpio_init(ui->dtr_pin);
+	gpio_set_dir(ui->dtr_pin, GPIO_OUT);
+	gpio_init(ui->dsr_pin);
+	gpio_set_dir(ui->dsr_pin, GPIO_IN);
+#endif
+
 	/* USB CDC LC */
 	ud->usb_lc.bit_rate = DEF_BIT_RATE;
 	ud->usb_lc.data_bits = DEF_DATA_BITS;
@@ -283,6 +302,16 @@ void init_uart_data(uint8_t itf) {
 			parity_usb2uart(ud->usb_lc.parity));
 }
 
+#ifdef LINE_CONTROL
+/* Invoked when line state has changed */
+void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts)
+{
+	const uart_id_t *ui = &UART_ID[itf];
+
+	gpio_put(ui->dtr_pin, dtr);
+}
+#endif
+
 int main(void)
 {
 	int itf;