From 157ad463a056792fd91b9bd9659758524432ab12 Mon Sep 17 00:00:00 2001 From: Rainer Radow Date: Sun, 31 Dec 2017 13:19:03 +0100 Subject: [PATCH 1/2] Update analogReference.adoc The 1.65V and 2.23V are not generated from a build in reference. They are only calculated by the devider 1/2 and 1/1.48 from the system Voltage. People who want to measure the battery voltage in a system with less than 3.3 Volt have to use the true 1V ref. If don't write this down here correct it can become quite frustrating and timeconsuming to try to measure a bat voltage with the so called 1.65 build in reference... Maybe you will find better words to explain it to the Arduino Community but the wording "build in reference" should only be used for the 1V reference! --- Language/Functions/Analog IO/analogReference.adoc | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/Language/Functions/Analog IO/analogReference.adoc b/Language/Functions/Analog IO/analogReference.adoc index 2db71ee8e..8cfcd281f 100644 --- a/Language/Functions/Analog IO/analogReference.adoc +++ b/Language/Functions/Analog IO/analogReference.adoc @@ -29,12 +29,13 @@ Arduino AVR Boards (Uno, Mega, etc.) Arduino SAMD Boards (Zero, etc.) -* AR_DEFAULT: the default analog reference of 3.3V -* AR_INTERNAL: a built-in 2.23V reference -* AR_INTERNAL1V0: a built-in 1.0V reference -* AR_INTERNAL1V65: a built-in 1.65V reference -* AR_INTERNAL2V23: a built-in 2.23V reference +* AR_DEFAULT: the default analog reference of 3.3V (VDDANA) +* AR_INTERNAL: 1/1.48 VDDANA (only for VDDANA > 2.0V) = 2.23V reference in a 3.3V system +* AR_INTERNAL1V0: a built-in 1.0V reference -> use this to measure your battery voltage! +* AR_INTERNAL1V65: 1/2 VDDANA = 1.65V reference in a 3.3 V system +* AR_INTERNAL2V23: 1/1.48 VDDANA (only for VDDANA > 2.0V) = 2.23V reference in a 3.3V system * AR_EXTERNAL: the voltage applied to the AREF pin is used as the reference +(For Details see Atmel SAMD21 Data sheet, 32.8.2 Reference Control) Arduino SAM Boards (Due) From a2930084f801d209f6abb369e6d0f418926c5b12 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Karl=20S=C3=B6derby?= <35461661+karlsoderby@users.noreply.github.com> Date: Fri, 1 Dec 2023 10:16:47 +0100 Subject: [PATCH 2/2] Update Language/Functions/Analog IO/analogReference.adoc --- Language/Functions/Analog IO/analogReference.adoc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Language/Functions/Analog IO/analogReference.adoc b/Language/Functions/Analog IO/analogReference.adoc index 8cfcd281f..e1948a414 100644 --- a/Language/Functions/Analog IO/analogReference.adoc +++ b/Language/Functions/Analog IO/analogReference.adoc @@ -35,7 +35,7 @@ Arduino SAMD Boards (Zero, etc.) * AR_INTERNAL1V65: 1/2 VDDANA = 1.65V reference in a 3.3 V system * AR_INTERNAL2V23: 1/1.48 VDDANA (only for VDDANA > 2.0V) = 2.23V reference in a 3.3V system * AR_EXTERNAL: the voltage applied to the AREF pin is used as the reference -(For Details see Atmel SAMD21 Data sheet, 32.8.2 Reference Control) +(For Details see Atmel SAMD21 Data sheet, 33.8.2 Reference Control) Arduino SAM Boards (Due)