diff --git a/libraries/AP_HAL_ChibiOS/hwdef/scripts/STM32H743xx.py b/libraries/AP_HAL_ChibiOS/hwdef/scripts/STM32H743xx.py
index e23099ff54..07f895bb7b 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/scripts/STM32H743xx.py
+++ b/libraries/AP_HAL_ChibiOS/hwdef/scripts/STM32H743xx.py
@@ -1278,6 +1278,8 @@ AltFunction_map = {
 
 ADC1_map = {
     # format is PIN : ADC1_CHAN
+	# "PA0_C":	0,	# not supported
+	# "PA1_C":	1,	# not supported
     "PF11"  :   2,
     "PA6"	:	3,
     "PC4"	:	4,
@@ -1299,6 +1301,9 @@ ADC1_map = {
 }
 
 ADC2_map = {
+	# format is PIN : ADC2_CHAN
+	# "PA0_C":	0,	# not supported
+	# "PA1_C":	1,	# not supported
     "PF13"	:	2,
     "PA6"	:	3,
     "PC4"	:	4,
@@ -1309,17 +1314,20 @@ ADC2_map = {
     "PB0"	:	9,
     "PC0"	:	10,
     "PC1"	:	11,
-    "PC2"	:	12,
-    "PC3"	:	13,
+	"PC2"	:	12,
+	"PC3"	:	13,
     "PA2"	:	14,
     "PA3"	:	15,
-    "N/A"	:	16,
-    "N/A"	:	17,
+    # ADC2_INP16 not implemented on H743
+    # ADC2_INP17 not implemented on H743
     "PA4"	:	18,
     "PA5"	:	19,
 }
 
 ADC3_map = {
+	# format is PIN : ADC3_CHAN
+	"PC2"	:	0,	# labeled PC2_C
+	"PC3"	:	1,	# labeled PC3_C
     "PF9"	:	2,
     "PF7"	:	3,
     "PF5"	:	4,
@@ -1328,6 +1336,9 @@ ADC3_map = {
     "PF8"	:	7,
     "PF6"	:	8,
     "PF4"	:	9,
+	"PC0"	:	10,
+	"PC1"	:	11,
+	# "PC2"	:	12,	# not supported, using the name "PC2" for PC2_C ADC3_INP0
     "PH2"	:	13,
     "PH3"	:	14,
     "PH4"	:	15,