diff --git a/firmware/common/portapack.c b/firmware/common/portapack.c
index ff383fbb..4bbb2312 100644
--- a/firmware/common/portapack.c
+++ b/firmware/common/portapack.c
@@ -423,6 +423,12 @@ void portapack_backlight(const bool on) {
 	portapack_io_write(1, portapack_if.io_reg);
 }
 
+void portapack_reference_oscillator(const bool on) {
+	const uint8_t mask = 1 << 6;
+	portapack_if.io_reg = (portapack_if.io_reg & ~mask) | (on ? mask : 0);
+	portapack_io_write(1, portapack_if.io_reg);
+}
+
 void portapack_fill_rectangle(
 	const ui_rect_t rect,
 	const ui_color_t color
diff --git a/firmware/common/portapack.h b/firmware/common/portapack.h
index 0157b39c..9febdbbd 100644
--- a/firmware/common/portapack.h
+++ b/firmware/common/portapack.h
@@ -68,6 +68,8 @@ const portapack_t* portapack_init(void);
 
 void portapack_backlight(const bool on);
 
+void portapack_reference_oscillator(const bool on);
+
 void portapack_fill_rectangle(
 	const ui_rect_t rect,
 	const ui_color_t color