diff --git a/firmware/export/adc.h b/firmware/export/adc.h
index a5ba583c38..3ae9dae215 100644
--- a/firmware/export/adc.h
+++ b/firmware/export/adc.h
@@ -74,7 +74,7 @@
 unsigned short adc_read(int channel);
 void adc_init(void);
 
-#ifdef IRIVER_H100_SERIES
+#if defined(IRIVER_H100_SERIES) || defined(IRIVER_H300_SERIES)
 unsigned char adc_scan(int channel);
 #endif