From bb509ec91dcc558752ad6768a2e26e0bc706fd71 Mon Sep 17 00:00:00 2001
From: sago35 <sago35@gmail.com>
Date: Tue, 4 May 2021 15:13:50 +0900
Subject: [PATCH] atsamd51, atsamd21: fix ADC.Get() value at 8bit and 10bit

---
 src/machine/machine_atsamd21.go | 13 ++++++++++++-
 src/machine/machine_atsamd51.go | 13 ++++++++++++-
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/machine/machine_atsamd21.go b/src/machine/machine_atsamd21.go
index e886f9373..76d6c5d49 100644
--- a/src/machine/machine_atsamd21.go
+++ b/src/machine/machine_atsamd21.go
@@ -433,7 +433,18 @@ func (a ADC) Get() uint16 {
 	sam.ADC.CTRLA.ClearBits(sam.ADC_CTRLA_ENABLE)
 	waitADCSync()
 
-	return uint16(val) << 4 // scales from 12 to 16-bit result
+	// scales to 16-bit result
+	switch (sam.ADC.CTRLB.Get() & sam.ADC_CTRLB_RESSEL_Msk) >> sam.ADC_CTRLB_RESSEL_Pos {
+	case sam.ADC_CTRLB_RESSEL_8BIT:
+		val = val << 8
+	case sam.ADC_CTRLB_RESSEL_10BIT:
+		val = val << 6
+	case sam.ADC_CTRLB_RESSEL_16BIT:
+		val = val << 4
+	case sam.ADC_CTRLB_RESSEL_12BIT:
+		val = val << 4
+	}
+	return val
 }
 
 func (a ADC) getADCChannel() uint8 {
diff --git a/src/machine/machine_atsamd51.go b/src/machine/machine_atsamd51.go
index a251f6704..0ce476ccc 100644
--- a/src/machine/machine_atsamd51.go
+++ b/src/machine/machine_atsamd51.go
@@ -863,7 +863,18 @@ func (a ADC) Get() uint16 {
 	for bus.SYNCBUSY.HasBits(sam.ADC_SYNCBUSY_ENABLE) {
 	}
 
-	return uint16(val) << 4 // scales from 12 to 16-bit result
+	// scales to 16-bit result
+	switch (bus.CTRLB.Get() & sam.ADC_CTRLB_RESSEL_Msk) >> sam.ADC_CTRLB_RESSEL_Pos {
+	case sam.ADC_CTRLB_RESSEL_8BIT:
+		val = val << 8
+	case sam.ADC_CTRLB_RESSEL_10BIT:
+		val = val << 6
+	case sam.ADC_CTRLB_RESSEL_16BIT:
+		val = val << 4
+	case sam.ADC_CTRLB_RESSEL_12BIT:
+		val = val << 4
+	}
+	return val
 }
 
 func (a ADC) getADCBus() *sam.ADC_Type {