From bb93ea1be47d6b4aa040c956eb36c09b4f1af433 Mon Sep 17 00:00:00 2001
From: Giuliano Zaro <3684609+GMagician@users.noreply.github.com>
Date: Wed, 13 Nov 2019 03:59:17 +0100
Subject: [PATCH] [SAMD51] Activate ADCs oversampled 12bits (#15874)

---
 Marlin/src/HAL/HAL_SAMD51/HAL.cpp | 4 +++-
 Marlin/src/HAL/HAL_SAMD51/HAL.h   | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/Marlin/src/HAL/HAL_SAMD51/HAL.cpp b/Marlin/src/HAL/HAL_SAMD51/HAL.cpp
index 1d7521270f..35863477e8 100644
--- a/Marlin/src/HAL/HAL_SAMD51/HAL.cpp
+++ b/Marlin/src/HAL/HAL_SAMD51/HAL.cpp
@@ -442,9 +442,11 @@ void HAL_adc_init() {
       // Preloaded data (fixed for all ADC instances hence not loaded by DMA)
       adc->REFCTRL.bit.REFSEL = ADC_REFCTRL_REFSEL_AREFA_Val;               // VRefA pin
       SYNC(adc->SYNCBUSY.bit.REFCTRL);
-      adc->CTRLB.bit.RESSEL = ADC_CTRLB_RESSEL_10BIT_Val;
+      adc->CTRLB.bit.RESSEL = ADC_CTRLB_RESSEL_12BIT_Val;
       SYNC(adc->SYNCBUSY.bit.CTRLB);
       adc->SAMPCTRL.bit.SAMPLEN = (6 - 1);                                  // Sampling clocks
+      adc->AVGCTRL.reg = ADC_AVGCTRL_SAMPLENUM_16 | ADC_AVGCTRL_ADJRES(4);  // 16 Accumulated conversions and shift 4 to get oversampled 12 bits result
+      SYNC(adc->SYNCBUSY.bit.AVGCTRL);
       // Registers loaded by DMA
       adc->DSEQCTRL.bit.INPUTCTRL = true;
 
diff --git a/Marlin/src/HAL/HAL_SAMD51/HAL.h b/Marlin/src/HAL/HAL_SAMD51/HAL.h
index 5966e958d4..dea84da5d1 100644
--- a/Marlin/src/HAL/HAL_SAMD51/HAL.h
+++ b/Marlin/src/HAL/HAL_SAMD51/HAL.h
@@ -109,8 +109,9 @@ extern uint16_t HAL_adc_result;     // result of last ADC conversion
 
 void HAL_adc_init();
 
+#define HAL_ADC_FILTERED            // Disable oversampling done in Marlin as ADC values already filtered in HAL
+#define HAL_ADC_RESOLUTION  12
 #define HAL_START_ADC(pin)  HAL_adc_start_conversion(pin)
-#define HAL_ADC_RESOLUTION  10
 #define HAL_READ_ADC()      HAL_adc_result
 #define HAL_ADC_READY()     true