d516cd8a9e
Battery (TechoBoard.h/cpp): Added PIN_VBAT_MEAS_EN (P0.31) — the T-Echo Lite has a gated voltage divider that must be enabled before reading. Also added pinMode(PIN_VBAT_READ, INPUT) before each ADC read to reclaim P0.02 from other peripherals. Pin definitions hardcoded from LilyGo's t_echo_lite_config.h. I2C (variant.h): Corrected SDA/SCL from P0.04/P0.02 to P1.04/P1.02 per LilyGo's IIC_1_SDA/IIC_1_SCL. The old P0.02 mapping conflicted with the battery ADC pin. GPS (variant.h): Corrected all five GPS pin assignments to match LilyGo's config — UART TX/RX, wake, PPS, and power enable were all scrambled. SPI (variant.h): Fixed SPI_INTERFACES_COUNT from _PINNUM(0, 2) to (2). Tested on T-Echo Lite Non-Shell (USB-C, no display). Battery readings match Heltec V4 reference within 10mV.
54 lines
1.4 KiB
C++
54 lines
1.4 KiB
C++
#include <Arduino.h>
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#include <Wire.h>
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#include "TechoBoard.h"
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#ifdef LILYGO_TECHO
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void TechoBoard::begin() {
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NRF52Board::begin();
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// Configure battery measurement control BEFORE Wire.begin()
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// to ensure P0.02 is not claimed by another peripheral
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pinMode(PIN_VBAT_MEAS_EN, OUTPUT);
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digitalWrite(PIN_VBAT_MEAS_EN, LOW);
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pinMode(PIN_VBAT_READ, INPUT);
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Wire.begin();
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pinMode(SX126X_POWER_EN, OUTPUT);
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digitalWrite(SX126X_POWER_EN, HIGH);
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delay(10);
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}
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uint16_t TechoBoard::getBattMilliVolts() {
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// Use LilyGo's exact ADC configuration
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analogReference(AR_INTERNAL_3_0);
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analogReadResolution(12);
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// Enable battery voltage divider (MOSFET gate on P0.31)
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pinMode(PIN_VBAT_MEAS_EN, OUTPUT);
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digitalWrite(PIN_VBAT_MEAS_EN, HIGH);
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// Reclaim P0.02 for analog input (in case another peripheral touched it)
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pinMode(PIN_VBAT_READ, INPUT);
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delay(10); // let divider + ADC settle
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// Read and average (matching LilyGo's approach)
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uint32_t sum = 0;
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for (int i = 0; i < 8; i++) {
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sum += analogRead(PIN_VBAT_READ);
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delayMicroseconds(100);
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}
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uint16_t adc = sum / 8;
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// Disable divider to save power
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digitalWrite(PIN_VBAT_MEAS_EN, LOW);
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// LilyGo's exact formula: adc * (3000.0 / 4096.0) * 2.0
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// = adc * 0.73242188 * 2.0 = adc * 1.46484375
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uint16_t millivolts = (uint16_t)((float)adc * (3000.0f / 4096.0f) * 2.0f);
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return millivolts;
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}
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#endif |