From b14d5c302a29f01a28266c68678f18d0f15c2fae Mon Sep 17 00:00:00 2001
From: Laurentiu Badea <laurb9@gmail.com>
Date: Sun, 4 Oct 2020 16:08:51 -0700
Subject: [PATCH] Update ESP32 wiring for TTGO T-Display board #73

Reference: https://github.com/Xinyuan-LilyGO/TTGO-T-Display
---
 examples/PanoController/PanoController.ino  |  2 +-
 examples/PanoController/config_esp32.h      | 48 +++++++++++----------
 examples/PanoController/platform_mecha_e1.h |  2 +-
 src/battery.cpp                             | 14 ++++--
 4 files changed, 39 insertions(+), 27 deletions(-)

diff --git a/examples/PanoController/PanoController.ino b/examples/PanoController/PanoController.ino
index b3f04e4..08be441 100644
--- a/examples/PanoController/PanoController.ino
+++ b/examples/PanoController/PanoController.ino
@@ -1,7 +1,7 @@
 /*
  * Pano Controller Firmware
  *
- * Copyright (C)2015-2017 Laurentiu Badea
+ * Copyright (C)2015-2020 Laurentiu Badea
  *
  * This file may be redistributed under the terms of the MIT license.
  * A copy of this license has been included with this distribution in the file LICENSE.
diff --git a/examples/PanoController/config_esp32.h b/examples/PanoController/config_esp32.h
index be560fb..44b06bf 100644
--- a/examples/PanoController/config_esp32.h
+++ b/examples/PanoController/config_esp32.h
@@ -1,39 +1,43 @@
 /*
  * Pano Controller Configuration File for ESP32 board
- * https://github.com/espressif/arduino-esp32/blob/master/docs/esp32_pinmap.png
- * https://desire.giesecke.tk/index.php/2018/07/06/reserved-gpios/
+ * Already wired in https://github.com/Xinyuan-LilyGO/TTGO-T-Display
+ * 19 TFT_MOSI
+ * 18 TFT_SCLK
+ * 5  TFT_CS
+ * 16 TFT_DC
+ * 4  TFT_BL
+ * 21 SDA
+ * 22 SCL
+ * 34 ADC_IN
+ * 35 BUTTON1
+ * 0  BUTTON2
+ * 14 ADC_POWER
+ * 
+ * Reserved GPIOs
+ * not as inputs: 0, 2, 6-11, 12, 15, 16, 17
+ * not as outputs:      6-11,         16, 17  34-39
+ * Reference https://desire.giesecke.tk/index.php/2018/07/06/reserved-gpios/
  */
 #include <Arduino.h>
 
-/* SPI (for display)
-SPI2 and SPI3 are general purpose SPI controllers, sometimes referred to as HSPI and VSPI
-SDA = IO 23
-SCLK = IO 18
-D/C = IO 21
-RST = IO 22
-CS = IO 5
-*/
-
 // Camera shutter controls
-#define CAMERA_FOCUS GPIO_NUM_16
-#define CAMERA_SHUTTER GPIO_NUM_17
+#define CAMERA_FOCUS   GPIO_NUM_37
+#define CAMERA_SHUTTER GPIO_NUM_38
 
 // Battery measurement pin R1/R2
-#define BATTERY GPIO_NUM_34 //34 # ADC1 CH0
+#define BATTERY GPIO_NUM_36 // ADC0
 
 // MPU (accel/gyro)
 // GPIO_NUM_21 I2C SDA
 // GPIO_NUM_22 I2C SCL
-#define MPU_INT GPIO_NUM_2
-#define MPU_VCC GPIO_NUM_4
+#define MPU_INT GPIO_NUM_13
+#define MPU_VCC GPIO_NUM_12
 
 // Future devices
 //#define COMPASS_DRDY xx
 
-// Stepper drivers control
-#define DIR GPIO_NUM_27
-#define VERT_STEP GPIO_NUM_25
+// Stepper drivers control. nENABLE, DIR are connected to both drivers
+#define nENABLE    GPIO_NUM_33
+#define DIR        GPIO_NUM_27
+#define VERT_STEP  GPIO_NUM_25
 #define HORIZ_STEP GPIO_NUM_26
-
-// this should be hooked up to nENABLE on both drivers
-#define nENABLE GPIO_NUM_14
diff --git a/examples/PanoController/platform_mecha_e1.h b/examples/PanoController/platform_mecha_e1.h
index f13a035..02d91bc 100644
--- a/examples/PanoController/platform_mecha_e1.h
+++ b/examples/PanoController/platform_mecha_e1.h
@@ -17,7 +17,7 @@
 
 // R1-R2[Ω] is the voltage divider: GND-[R1]-[ADC Input]-[R2]-Vin
 // measure resistors/pot and enter actual values for more accurate measure
-#define BATT_R1 7060
+#define BATT_R1 6674
 #define BATT_R2 42600
 
 #endif // PLATFORM_MECHA_E1
diff --git a/src/battery.cpp b/src/battery.cpp
index 2617ac3..fcba934 100644
--- a/src/battery.cpp
+++ b/src/battery.cpp
@@ -1,7 +1,7 @@
 /*
  * Battery status
  *
- * Copyright (C)2016-2017 Laurentiu Badea
+ * Copyright (C)2016-2020 Laurentiu Badea
  *
  * This file may be redistributed under the terms of the MIT license.
  * A copy of this license has been included with this distribution in the file LICENSE.
@@ -13,20 +13,28 @@ Battery::Battery(int battery_pin, int r1, int r2, int vcc)
 :battery_pin(battery_pin), r1(r1), r2(r2), vcc(vcc)
 {}
 
+#define ADC_BITS 10
+
 void Battery::begin(void){
     // Configure input pin and ADC for reading battery voltage
     pinMode(battery_pin, INPUT);
 #if defined(__MK20DX256__) || defined(__MKL26Z64__)
-    analogReadRes(10);
+    analogReadRes(ADC_BITS);
     analogReadAveraging(32);
 #endif
+#if defined(ESP32)
+    // ESP32 ADC is non-linear, so the measured voltage not accurate
+    // https://github.com/espressif/arduino-esp32/issues/1804#issuecomment-475281577
+    vcc = 3500;
+    analogReadResolution(ADC_BITS); // ESP32 default is 12
+#endif
 }
 
 /*
  * Return battery voltage, in mV
  */
 int Battery::voltage(void){
-    return map(analogRead(battery_pin), 0, (1<<10)-1, 0, (vcc * (r1 + r2) / r1)/100) * 100;
+    return map(analogRead(battery_pin), 1, (1<<ADC_BITS)-1, 0, (vcc * (r1 + r2) / r1)/100) * 100;
 }
 
 /*