From eb766aa27f7f9d14c012c7cdde8a7932ed8dcdbd Mon Sep 17 00:00:00 2001
From: pmantoine <pma-github@milleng.com.au>
Date: Wed, 12 Oct 2022 17:12:00 +0800
Subject: [PATCH] Fix to SAMD21 ADCee pin init

---
 DCCTimerSAMD.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/DCCTimerSAMD.cpp b/DCCTimerSAMD.cpp
index df11b1e..4c04276 100644
--- a/DCCTimerSAMD.cpp
+++ b/DCCTimerSAMD.cpp
@@ -164,12 +164,16 @@ int ADCee::init(uint8_t pin) {
 
   if (id > NUM_ADC_INPUTS)
     return -1023;
-  pinMode(pin, INPUT);
+//  pinMode(pin, INPUT);
   int value = analogRead(pin);
   if (analogvals == NULL)
     analogvals = (int *)calloc(NUM_ADC_INPUTS+1, sizeof(int));
   analogvals[id] = value;
   usedpins |= (1<<id);
+
+  // Permanently configure SAMD IO MUX for that pin
+  pinPeripheral(pin, PIO_ANALOG);
+  ADC->INPUTCTRL.bit.MUXPOS = g_APinDescription[pin].ulADCChannelNumber; // Selection for the positive ADC input
   
   return value;
 }