From de4f5be67f90e0515ca5dd278f584d02c8b625c9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20F=C3=BCrmann?= <fuermannj@gmail.com>
Date: Fri, 21 Nov 2025 16:38:05 +0100
Subject: [PATCH] Fix wireless paper build

---
 .../heltec_wireless_paper/HeltecV3Board.h     | 97 +++++++++++++++++++
 variants/heltec_wireless_paper/platformio.ini |  7 ++
 variants/heltec_wireless_paper/target.h       |  2 +-
 3 files changed, 105 insertions(+), 1 deletion(-)
 create mode 100644 variants/heltec_wireless_paper/HeltecV3Board.h

diff --git a/variants/heltec_wireless_paper/HeltecV3Board.h b/variants/heltec_wireless_paper/HeltecV3Board.h
new file mode 100644
index 000000000..afdaf6398
--- /dev/null
+++ b/variants/heltec_wireless_paper/HeltecV3Board.h
@@ -0,0 +1,97 @@
+#pragma once
+
+#include <Arduino.h>
+#include <helpers/RefCountedDigitalPin.h>
+#include <helpers/ESP32Board.h>
+
+// built-ins
+#ifndef PIN_VBAT_READ              // set in platformio.ini for boards like Heltec Wireless Paper (20)
+  #define  PIN_VBAT_READ    1
+#endif
+#ifndef PIN_ADC_CTRL              // set in platformio.ini for Heltec Wireless Tracker (2)
+  #define  PIN_ADC_CTRL    37
+#endif
+#define  PIN_ADC_CTRL_ACTIVE    LOW
+#define  PIN_ADC_CTRL_INACTIVE  HIGH
+
+#include <driver/rtc_io.h>
+
+class HeltecV3Board : public ESP32Board {
+private:
+  bool adc_active_state;
+
+public:
+  RefCountedDigitalPin periph_power;
+
+  HeltecV3Board() : periph_power(PIN_VEXT_EN) { }
+
+  void begin() {
+    ESP32Board::begin();
+
+    // Auto-detect correct ADC_CTRL pin polarity (different for boards >3.2)
+    pinMode(PIN_ADC_CTRL, INPUT);
+    adc_active_state = !digitalRead(PIN_ADC_CTRL);
+
+    pinMode(PIN_ADC_CTRL, OUTPUT);
+    digitalWrite(PIN_ADC_CTRL, !adc_active_state); // Initially inactive
+
+    periph_power.begin();
+
+    esp_reset_reason_t reason = esp_reset_reason();
+    if (reason == ESP_RST_DEEPSLEEP) {
+      long wakeup_source = esp_sleep_get_ext1_wakeup_status();
+      if (wakeup_source & (1 << P_LORA_DIO_1)) {  // received a LoRa packet (while in deep sleep)
+        startup_reason = BD_STARTUP_RX_PACKET;
+      }
+
+      rtc_gpio_hold_dis((gpio_num_t)P_LORA_NSS);
+      rtc_gpio_deinit((gpio_num_t)P_LORA_DIO_1);
+    }
+  }
+
+  void enterDeepSleep(uint32_t secs, int pin_wake_btn = -1) {
+    esp_sleep_pd_config(ESP_PD_DOMAIN_RTC_PERIPH, ESP_PD_OPTION_ON);
+
+    // Make sure the DIO1 and NSS GPIOs are hold on required levels during deep sleep
+    rtc_gpio_set_direction((gpio_num_t)P_LORA_DIO_1, RTC_GPIO_MODE_INPUT_ONLY);
+    rtc_gpio_pulldown_en((gpio_num_t)P_LORA_DIO_1);
+
+    rtc_gpio_hold_en((gpio_num_t)P_LORA_NSS);
+
+    if (pin_wake_btn < 0) {
+      esp_sleep_enable_ext1_wakeup( (1L << P_LORA_DIO_1), ESP_EXT1_WAKEUP_ANY_HIGH);  // wake up on: recv LoRa packet
+    } else {
+      esp_sleep_enable_ext1_wakeup( (1L << P_LORA_DIO_1) | (1L << pin_wake_btn), ESP_EXT1_WAKEUP_ANY_HIGH);  // wake up on: recv LoRa packet OR wake btn
+    }
+
+    if (secs > 0) {
+      esp_sleep_enable_timer_wakeup(secs * 1000000);
+    }
+
+    // Finally set ESP32 into sleep
+    esp_deep_sleep_start();   // CPU halts here and never returns!
+  }
+
+  void powerOff() override {
+    enterDeepSleep(0);
+  }
+
+  uint16_t getBattMilliVolts() override {
+    analogReadResolution(10);
+    digitalWrite(PIN_ADC_CTRL, adc_active_state);
+
+    uint32_t raw = 0;
+    for (int i = 0; i < 8; i++) {
+      raw += analogRead(PIN_VBAT_READ);
+    }
+    raw = raw / 8;
+
+    digitalWrite(PIN_ADC_CTRL, !adc_active_state);
+
+    return (5.42 * (3.3 / 1024.0) * raw) * 1000;
+  }
+
+  const char* getManufacturerName() const override {
+    return "Heltec V3";
+  }
+};
diff --git a/variants/heltec_wireless_paper/platformio.ini b/variants/heltec_wireless_paper/platformio.ini
index c9ad758b1..68909bac9 100644
--- a/variants/heltec_wireless_paper/platformio.ini
+++ b/variants/heltec_wireless_paper/platformio.ini
@@ -9,6 +9,13 @@ build_flags =
   -D WRAPPER_CLASS=CustomSX1262Wrapper
   -D LORA_TX_POWER=22
   -D P_LORA_TX_LED=18
+  -D P_LORA_DIO_1=14
+  -D P_LORA_NSS=8
+  -D P_LORA_RESET=12
+  -D P_LORA_BUSY=13
+  -D P_LORA_SCLK=9
+  -D P_LORA_MISO=11
+  -D P_LORA_MOSI=10
   ; -D PIN_BOARD_SDA=17
   ; -D PIN_BOARD_SCL=18
   -D PIN_USER_BTN=0
diff --git a/variants/heltec_wireless_paper/target.h b/variants/heltec_wireless_paper/target.h
index 65b972d0e..f143c2f64 100644
--- a/variants/heltec_wireless_paper/target.h
+++ b/variants/heltec_wireless_paper/target.h
@@ -3,7 +3,7 @@
 #define RADIOLIB_STATIC_ONLY 1
 #include <RadioLib.h>
 #include <helpers/radiolib/RadioLibWrappers.h>
-#include <helpers/HeltecV3Board.h>
+#include "HeltecV3Board.h"
 #include <helpers/radiolib/CustomSX1262Wrapper.h>
 #include <helpers/AutoDiscoverRTCClock.h>
 #include <helpers/SensorManager.h>