2.5dB could be a more appropriate attenuation for heltec ADCs (#2511)

Co-authored-by: Ben Meadors <benmmeadors@gmail.com>
meshtastic · May 26, 2023 · 7475c86 · 7475c86
1 parent f3af3c1
commit 7475c86
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Showing 3 changed files with 6 additions and 1 deletion.
diff --git a/src/Power.cpp b/src/Power.cpp
@@ -30,8 +30,11 @@ RTC_NOINIT_ATTR uint64_t RTC_reg_b;
 #endif // BAT_MEASURE_ADC_UNIT
 
 esp_adc_cal_characteristics_t *adc_characs = (esp_adc_cal_characteristics_t *)calloc(1, sizeof(esp_adc_cal_characteristics_t));
-
+#ifndef ADC_ATTENUATION
 static const adc_atten_t atten = ADC_ATTEN_DB_11;
+#else
+static const adc_atten_t atten = ADC_ATTENUATION;
+#endif
 #endif // BATTERY_PIN && ARCH_ESP32
 
 #ifdef HAS_PMU

diff --git a/variants/heltec_v3/variant.h b/variants/heltec_v3/variant.h
@@ -9,6 +9,7 @@
 
 #define BATTERY_PIN 1 // A battery voltage measurement pin, voltage divider connected here to measure battery voltage
 #define ADC_CHANNEL ADC1_GPIO1_CHANNEL
+#define ADC_ATTENUATION ADC_ATTEN_DB_2_5 // lower dB for high resistance voltage divider
 #define ADC_MULTIPLIER 4.9
 
 #define USE_SX1262

diff --git a/variants/heltec_wsl_v3/variant.h b/variants/heltec_wsl_v3/variant.h
@@ -10,6 +10,7 @@
 
 #define BATTERY_PIN 1 // A battery voltage measurement pin, voltage divider connected here to measure battery voltage
 #define ADC_CHANNEL ADC1_GPIO1_CHANNEL
+#define ADC_ATTENUATION ADC_ATTEN_DB_2_5 // lower dB for high resistance voltage divider
 #define ADC_MULTIPLIER 4.9
 
 #define USE_SX1262