From 19d8b0e625e9e088800b02d56f0f6c198cce8a81 Mon Sep 17 00:00:00 2001
From: David Antliff <david@pitchblende.co.nz>
Date: Thu, 23 Apr 2020 15:36:45 +1200
Subject: [PATCH] Support for parasitic power - WIP.

---
 CMakeLists.txt           |  2 +-
 components/esp32-ds18b20 |  2 +-
 main/app_main.c          | 25 +++++++++++++++++++------
 3 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 31da009..f0e3c48 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,7 +3,7 @@
 cmake_minimum_required(VERSION 3.5)
 
 include($ENV{IDF_PATH}/tools/cmake/project.cmake)
-project(esp32-ds18b20-example)
+project(esp32-ds18b20-example LANGUAGES C)
 
 if (NOT IDF_VERSION_MAJOR)
   set(IDF_VERSION_MAJOR 3)
diff --git a/components/esp32-ds18b20 b/components/esp32-ds18b20
index d76b70c..ae81f86 160000
--- a/components/esp32-ds18b20
+++ b/components/esp32-ds18b20
@@ -1 +1 @@
-Subproject commit d76b70c0a795adbbd1b9d1b3e2789b455cfd945d
+Subproject commit ae81f86e0ee1cd65b6d6a2ad59deb7ba295ab3c4
diff --git a/main/app_main.c b/main/app_main.c
index d0705ec..14c99b9 100644
--- a/main/app_main.c
+++ b/main/app_main.c
@@ -22,8 +22,6 @@
  * SOFTWARE.
  */
 
-#include <inttypes.h>
-
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 #include "esp_system.h"
@@ -38,10 +36,11 @@
 #define DS18B20_RESOLUTION   (DS18B20_RESOLUTION_12_BIT)
 #define SAMPLE_PERIOD        (1000)   // milliseconds
 
-void app_main()
+_Noreturn void app_main()
 {
     // Override global log level
     esp_log_level_set("*", ESP_LOG_INFO);
+    esp_log_level_set("*", ESP_LOG_DEBUG);
 
     // To debug, use 'make menuconfig' to set default Log level to DEBUG, then uncomment:
     //esp_log_level_set("owb", ESP_LOG_DEBUG);
@@ -150,6 +149,14 @@ void app_main()
 //        vTaskDelay(1000 / portTICK_PERIOD_MS);
 //    }
 
+    // Check for parasitic-powered devices that require a strong-pullup
+    bool require_strong_pullup = false;
+    ds18b20_check_for_parasite_power(owb, &require_strong_pullup);
+    printf("Strong pullup (parasitic power) %srequired\n", require_strong_pullup ? "" : "not ");
+    if (require_strong_pullup)
+    {
+    }
+
     // Read temperatures more efficiently by starting conversions on all devices at the same time
     int errors_count[MAX_DEVICES] = {0};
     int sample_count = 0;
@@ -157,15 +164,21 @@ void app_main()
     {
         TickType_t last_wake_time = xTaskGetTickCount();
 
-        while (1)
-        {
+        while (1) {
             last_wake_time = xTaskGetTickCount();
 
             ds18b20_convert_all(owb);
 
             // In this application all devices use the same resolution,
             // so use the first device to determine the delay
-            ds18b20_wait_for_conversion(devices[0]);
+            if (require_strong_pullup) {
+                ets_delay_us(750000);
+                gpio_set_level(5, 0);
+            }
+            else
+            {
+                ds18b20_wait_for_conversion(devices[0]);
+            }
 
             // Read the results immediately after conversion otherwise it may fail
             // (using printf before reading may take too long)