From f0380459b447bf3b65d31cd91ec4922611fa4ffb Mon Sep 17 00:00:00 2001
From: deadprogram <ron@hybridgroup.com>
Date: Sat, 26 Sep 2026 15:27:10 +0200
Subject: [PATCH] machine/esp32c6: add default UART0 pins

UART.Configure had no default pins, so Configure(UARTConfig{}) returned
errSamePins and -serial=uart gave no output. Use GPIO16 and GPIO17, the
defaults from ESP-IDF soc/esp32c6/include/soc/uart_pins.h.
---
 src/machine/machine_esp32c6.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/machine/machine_esp32c6.go b/src/machine/machine_esp32c6.go
index e6b7988dd7..6fd1bc0585 100644
--- a/src/machine/machine_esp32c6.go
+++ b/src/machine/machine_esp32c6.go
@@ -328,6 +328,11 @@ func (uart *UART) Configure(config UARTConfig) error {
 	if config.BaudRate == 0 {
 		config.BaudRate = 115200
 	}
+	if uart.Bus == esp.UART0 && config.TX == 0 && config.RX == 0 {
+		// Default UART0 pins. See ESP-IDF soc/esp32c6/include/soc/uart_pins.h.
+		config.TX = GPIO16
+		config.RX = GPIO17
+	}
 	if config.TX == config.RX {
 		return errSamePins
 	}