diff --git a/src/machine/board_esp32c3-supermini.go b/src/machine/board_esp32c3-supermini.go
index 3e1aad1a..63e1e7bf 100644
--- a/src/machine/board_esp32c3-supermini.go
+++ b/src/machine/board_esp32c3-supermini.go
@@ -53,4 +53,5 @@ const (
 	SPI_MISO_PIN = GPIO5
 	SPI_MOSI_PIN = GPIO6
 	SPI_SS_PIN   = GPIO7
+	SPI_SCK_PIN  = GPIO4
 )