From 5815835295db926da04a502926ebe6f2059c0118 Mon Sep 17 00:00:00 2001 From: SarenT Date: Thu, 9 Aug 2018 06:32:38 +0200 Subject: [PATCH 1/4] Analog input voltage can be 3.3V According to this tutorial and my personal test with my Amica, 1.0V delivers 320 and 3.3V delivers 1024 at 10-bit resolution. I guess 3.3V is possible. --- doc/reference.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/doc/reference.rst b/doc/reference.rst index fbff990f93..3e6ba79785 100644 --- a/doc/reference.rst +++ b/doc/reference.rst @@ -42,7 +42,7 @@ either to read voltage at ADC pin, or to read module supply voltage (VCC). To read external voltage applied to ADC pin, use ``analogRead(A0)``. -Input voltage range is 0 — 1.0V. +Input voltage range is 0 — 1.0V or 0 — 3.3V. To read VCC voltage, use ``ESP.getVcc()`` and ADC pin must be kept unconnected. Additionally, the following line has to be added to the From 21de4c3f945473a25e4b116745a00cb8b0909320 Mon Sep 17 00:00:00 2001 From: SarenT Date: Thu, 9 Aug 2018 14:44:38 +0200 Subject: [PATCH 2/4] Update reference.rst Added warnings. --- doc/reference.rst | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/doc/reference.rst b/doc/reference.rst index 3e6ba79785..921edf2361 100644 --- a/doc/reference.rst +++ b/doc/reference.rst @@ -42,7 +42,11 @@ either to read voltage at ADC pin, or to read module supply voltage (VCC). To read external voltage applied to ADC pin, use ``analogRead(A0)``. -Input voltage range is 0 — 1.0V or 0 — 3.3V. +Input voltage range is 0 — 1.0V or 0 — 3.3V (Be aware that some boards +use internal voltage dividers. Exposing ESP8266 A0 pin to 3.3V might +damage it. Please refer to the documentation of your board or try +readings with 1.0V first to see if the value is 1024 or way less (e.g. +~320)). To read VCC voltage, use ``ESP.getVcc()`` and ADC pin must be kept unconnected. Additionally, the following line has to be added to the From fc89c7d50668e6dbe4ff80bcf229beb032231811 Mon Sep 17 00:00:00 2001 From: SarenT Date: Thu, 9 Aug 2018 19:10:17 +0200 Subject: [PATCH 3/4] Update reference.rst --- doc/reference.rst | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/doc/reference.rst b/doc/reference.rst index 921edf2361..06240f0cfa 100644 --- a/doc/reference.rst +++ b/doc/reference.rst @@ -42,11 +42,7 @@ either to read voltage at ADC pin, or to read module supply voltage (VCC). To read external voltage applied to ADC pin, use ``analogRead(A0)``. -Input voltage range is 0 — 1.0V or 0 — 3.3V (Be aware that some boards -use internal voltage dividers. Exposing ESP8266 A0 pin to 3.3V might -damage it. Please refer to the documentation of your board or try -readings with 1.0V first to see if the value is 1024 or way less (e.g. -~320)). +Input voltage range is 0 — 1.0V, however some breakout boards may implement voltage dividers. To read VCC voltage, use ``ESP.getVcc()`` and ADC pin must be kept unconnected. Additionally, the following line has to be added to the From f0dc9735091b8eda3212dd8ef3029c6ca997bb50 Mon Sep 17 00:00:00 2001 From: SarenT Date: Mon, 13 Aug 2018 23:01:41 +0200 Subject: [PATCH 4/4] Update reference.rst requested changes --- doc/reference.rst | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/doc/reference.rst b/doc/reference.rst index 06240f0cfa..62c1d04aef 100644 --- a/doc/reference.rst +++ b/doc/reference.rst @@ -42,7 +42,12 @@ either to read voltage at ADC pin, or to read module supply voltage (VCC). To read external voltage applied to ADC pin, use ``analogRead(A0)``. -Input voltage range is 0 — 1.0V, however some breakout boards may implement voltage dividers. +Input voltage range of bare ESP8266 is 0 — 1.0V, however some many +boards may implement voltage dividers. To be on the safe side, <1.0V +can be tested. If e.g. 0.5V delivers values around ~512, then maximum +voltage is very likely to be 1.0V and 3.3V may harm the ESP8266. +However values around ~150 indicates that the maximum voltage is +likely to be 3.3V. To read VCC voltage, use ``ESP.getVcc()`` and ADC pin must be kept unconnected. Additionally, the following line has to be added to the