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Description
Board
ESP32-C6 Zero
Device Description
Hardware Configuration
GPIO3 is pulled-up via 10k to 3v3
Version
v3.2.0
IDE Name
Arduino IDE 1.8.13
Operating System
Windows 10
Flash frequency
80 MHz
PSRAM enabled
yes
Upload speed
921600
Description
I have a board with GPIO3 pulled up to 3v3 via 10k resistor. I've tried the same experiment with GPIO0. The bug is still the same: when performing analogRead(GPIO_number), I expect to get maximum ADC reading (4095 by default or 2047 if analogReadResolution(11); was called) and something close to 3300 mV when analogReadMilliVolts() is called. But I keep receiving ADC values of 3360 (1680 in 11-bit mode) but with right millivolts of around 3300.
Another thing that I've noticed is that pinMode(GPIO_number, INPUT_PULLUP) does nothing.
Have tried 2 different boards, both ESP cores of 3.1.13 and 3.2.0, and different PCs. The bug is still the same.
I've left commented out ADC settings in setup() so you can reproduce the problem and see it at different resolutions.
Sketch
const uint8_t ANALOG_PIN = 3;
void setup()
{
Serial.begin(115200);
pinMode(ANALOG_PIN, INPUT);
// analogReadResolution(12);
// analogSetAttenuation(ADC_11db);
}
void loop()
{
int sensorValue = analogRead(ANALOG_PIN);
int millivolts = analogReadMilliVolts(ANALOG_PIN);
Serial.println("-------------");
Serial.print("ADC value: ");
Serial.print(sensorValue);
Serial.print(" in millivolts: ");
Serial.print(millivolts);
Serial.println();
delay(10);
}Debug Message
Chip Info:
------------------------------------------
Model : ESP32-C6
Package : 1
Revision : 0.01
Cores : 1
CPU Frequency : 80 MHz
XTAL Frequency : 40 KB, type: DATA, subtype: NVS
otadata : addr: 0x0000E000, size: 8.0 KB, type: DATA, subtype: OTA
app0 : addr: 0x00010000, size: 1280.0 KB, type: APP, subtype: OTA_0
app1 : addr: 0x00150000, size: 1280.0 KB, type: APP, subtype: OTA_1
spiffs : addr: 0x00290000, size: 1408.0 KB, type: DATA, subtype: SPIFFS
coredump : addr: 0x003F0000, size: 64.0 KB, type: DATA, subtype: COREDUMP
------------------------------------------
Software Info:
------------------------------------------
Compile Date/Time : Apr 29 2025 18:53:54
Compile Host OS : windows
ESP-IDF Version : v5.4.1-1-g2f7dcd862a-dirty
Arduino Version : 3.2.0
------------------------------------------
Board Info:
------------------------------------------
Arduino Board : ESP32C6_DEV
Arduino Variant : esp32c6
Arduino FQBN : esp32:esp32:esp32c6:JTAGAdapter=default,CDCOnBoot=cdc,PartitionScheme=default,CPUFreq=80,FlashMode=qio,FlashFreq=80,FlashSize=4M,UploadSpeed=921600,DebugLevel=verbose,EraseFlash=none,ZigbeeMode=default
============ Before Setup End ============
[101155][I][esp32-hal-periman.c:141] perimanSetPinBus(): Pin 12 already has type USB_DM (38) with bus 0x4080ee20
[101157][I][esp32-hal-periman.c:141] perimanSetPinBus(): Pin 13 already has type USB_DP (39) with bus 0x4080ee20
[101158][V][esp32-hal-periman.c:235] perimanSetBusDeinit(): Deinit function for type GPIO (1) successfully set to 0x42000590
[101159][V][esp32-hal-periman.c:160] perimanSetPinBus(): Pin 3 successfully set to type GPIO (1) with bus 0x4
=========== After Setup Start ============
INTERNAL Memory Info:
------------------------------------------
Total Size : 470576 B ( 459.5 KB)
Free Bytes : 436432 B ( 426.2 KB)
Allocated Bytes : 27608 B ( 27.0 KB)
Minimum Free Bytes: 431532 B ( 421.4 KB)
Largest Free Block: 401396 B ( 392.0 KB)
------------------------------------------
GPIO Info:
------------------------------------------
GPIO : BUS_TYPE[bus/unit][chan]
--------------------------------------
3 : GPIO
12 : USB_DM
13 : USB_DP
16 : UART_TX[0]
17 : UART_RX[0]
============ After Setup End =============
[101191][D][esp32-hal-adc.c:272] __analogRead(): Calling __analogInit! pin = 3
[101192][V][esp32-hal-periman.c:235] perimanSetBusDeinit(): Deinit function for type ADC_ONESHOT (7) successfully set to 0x420000ba
[101193][V][esp32-hal-periman.c:160] perimanSetPinBus(): Pin 3 successfully set to type ADC_ONESHOT (7) with bus 0x4
[101195][D][esp32-hal-adc.c:305] __analogReadMilliVolts(): Creating cali handle for ADC_0
-------------
ADC value: 3360 in millivolts: 3318
-------------
ADC value: 3360 in millivolts: 3318
-------------
ADC value: 3361 in millivolts: 3317
Other Steps to Reproduce
Works perfectly on ESP32-C3 SuperMini.
I have checked existing issues, online documentation and the Troubleshooting Guide
- I confirm I have checked existing issues, online documentation and Troubleshooting guide.