From 3c7180fefad58254f8813845bf8142634254bd56 Mon Sep 17 00:00:00 2001
From: rbaron <rbaron@rbaron.net>
Date: Sun, 28 Mar 2021 10:44:33 +0200
Subject: [PATCH] Adds run_counter to ble advertising packet

---
 code/b-parasite/config/prst_config.h | 15 +++++++++-----
 code/b-parasite/src/main.c           |  9 ++++++---
 code/b-parasite/src/prst/ble.c       | 30 ++++++++++++++++++----------
 code/b-parasite/src/prst/ble.h       |  3 ++-
 4 files changed, 37 insertions(+), 20 deletions(-)

diff --git a/code/b-parasite/config/prst_config.h b/code/b-parasite/config/prst_config.h
index e8e1f01..ff4e331 100644
--- a/code/b-parasite/config/prst_config.h
+++ b/code/b-parasite/config/prst_config.h
@@ -7,7 +7,7 @@
 #define PRST_LED_PIN NRF_GPIO_PIN_MAP(0, 28)
 
 // Deep sleep.
-#define PRST_DEEP_SLEEP_IN_SECONDS 3
+#define PRST_DEEP_SLEEP_IN_SECONDS 300
 
 // Analog to digital converter (ADC).
 // Prints out ADC debug info, such as the values read for battery and soil
@@ -17,10 +17,15 @@
 // BLE.
 // Prints out BLE debug info, such as the final encoded advertisement packet.
 #define PRST_BLE_DEBUG 0
-#define PRST_BLE_MAC_ADDR_LSB0 0xaa
-#define PRST_BLE_MAC_ADDR_LSB1 0xbb
-#define PRST_BLE_ADV_TIME_IN_MS 200
-#define PRST_BLE_ADV_NAME "prst aabb"
+#define PRST_BLE_PROTOCOL_VERSION 1
+#define PRST_BLE_MAC_ADDR_LSB1 0x00
+#define PRST_BLE_MAC_ADDR_LSB0 0x01
+#define PRST_BLE_ADV_NAME "prst"
+// Total time spend advertising.
+#define PRST_BLE_ADV_TIME_IN_MS 1000
+// Interval between advertising packets.
+// From the specs, this value has to be greater or equal 20ms.
+#define PRST_BLE_ADV_INTERVAL_IN_MS 30
 
 // PWM.
 #define PRST_PWM_PIN NRF_GPIO_PIN_MAP(0, 5)
diff --git a/code/b-parasite/src/main.c b/code/b-parasite/src/main.c
index 6b12d1a..d88473a 100644
--- a/code/b-parasite/src/main.c
+++ b/code/b-parasite/src/main.c
@@ -22,12 +22,14 @@
 #include "prst/shtc3.h"
 #include "prst_config.h"
 
-#define DEAD_BEEF 0xDEADBEEF
-
+// #define DEAD_BEEF 0xDEADBEEF
 // void assert_nrf_callback(uint16_t line_num, const uint8_t *p_file_name) {
 //   app_error_handler(DEAD_BEEF, line_num, p_file_name);
 // }
 
+// A small wrap-around counter for deduplicating BLE packets on the receiver.
+static uint8_t run_counter = 0;
+
 static void log_init(void) {
   ret_code_t err_code = NRF_LOG_INIT(NULL);
   APP_ERROR_CHECK(err_code);
@@ -68,13 +70,14 @@ static void rtc_callback() {
   prst_pwm_stop();
   nrf_gpio_pin_clear(PRST_FAST_DISCH_PIN);
   prst_ble_update_adv_data(batt_read.millivolts, temp_humi.temp_millicelcius,
-                           temp_humi.humidity, soil_read.relative);
+                           temp_humi.humidity, soil_read.relative, run_counter);
   NRF_LOG_FLUSH();
   prst_adv_start();
   nrf_delay_ms(PRST_BLE_ADV_TIME_IN_MS);
   prst_adv_stop();
   nrf_gpio_pin_clear(PRST_LED_PIN);
   NRF_LOG_FLUSH();
+  run_counter++;
 }
 
 int main(void) {
diff --git a/code/b-parasite/src/prst/ble.c b/code/b-parasite/src/prst/ble.c
index b465cdb..f7aac3a 100644
--- a/code/b-parasite/src/prst/ble.c
+++ b/code/b-parasite/src/prst/ble.c
@@ -20,7 +20,8 @@
 // The connection to configure. We only have the one.
 #define PRST_CONN_CFG_TAG 1
 
-#define NON_CONNECTABLE_ADV_INTERVAL MSEC_TO_UNITS(100, UNIT_0_625_MS)
+#define NON_CONNECTABLE_ADV_INTERVAL \
+  MSEC_TO_UNITS(PRST_BLE_ADV_INTERVAL_IN_MS, UNIT_0_625_MS)
 
 // Sensor data payload that will go into the advertisement message.
 #define SERVICE_DATA_LEN 12
@@ -93,7 +94,8 @@ static void init_advertisement_data() {
       sd_ble_gap_adv_set_configure(&adv_handle_, &gap_adv_data_, &adv_params_);
   APP_ERROR_CHECK(err_code);
 
-  APP_ERROR_CHECK(sd_ble_gap_addr_set(&gap_addr_));
+  // Four bits for the protocol version
+  service_data[0] = (PRST_BLE_PROTOCOL_VERSION << 4) & 0xf0;
 }
 
 void prst_ble_init() {
@@ -112,23 +114,29 @@ void prst_ble_init() {
   err_code = nrf_sdh_ble_enable(&ram_start);
   APP_ERROR_CHECK(err_code);
 
+  APP_ERROR_CHECK(sd_ble_gap_addr_set(&gap_addr_));
+
   init_advertisement_data();
 }
 
 void prst_ble_update_adv_data(uint16_t batt_millivolts,
                               uint16_t temp_millicelcius, uint16_t humidity,
-                              uint16_t soil_moisture) {
-  service_data[0] = batt_millivolts >> 8;
-  service_data[1] = batt_millivolts & 0xff;
+                              uint16_t soil_moisture, uint8_t run_counter) {
+  // 4 bits for a small wrap-around counter for deduplicating messages on the
+  // receiver.
+  service_data[1] = run_counter & 0x0f;
 
-  service_data[2] = temp_millicelcius >> 8;
-  service_data[3] = temp_millicelcius & 0xff;
+  service_data[2] = batt_millivolts >> 8;
+  service_data[3] = batt_millivolts & 0xff;
 
-  service_data[4] = humidity >> 8;
-  service_data[5] = humidity & 0xff;
+  service_data[4] = temp_millicelcius >> 8;
+  service_data[5] = temp_millicelcius & 0xff;
 
-  service_data[6] = soil_moisture >> 8;
-  service_data[7] = soil_moisture & 0xff;
+  service_data[6] = humidity >> 8;
+  service_data[7] = humidity & 0xff;
+
+  service_data[8] = soil_moisture >> 8;
+  service_data[9] = soil_moisture & 0xff;
 
   // Encodes adv_data_ into .gap_adv_data_.
   uint32_t err_code = ble_advdata_encode(
diff --git a/code/b-parasite/src/prst/ble.h b/code/b-parasite/src/prst/ble.h
index 851cd99..df7bdb9 100644
--- a/code/b-parasite/src/prst/ble.h
+++ b/code/b-parasite/src/prst/ble.h
@@ -13,6 +13,7 @@ void prst_adv_stop();
 
 void prst_ble_update_adv_data(uint16_t batt_millivolts,
                               uint16_t temp_millicelcius, uint16_t humidity,
-                              uint16_t soil_moisture);
+                              uint16_t soil_moisture,
+                              uint8_t run_counter);
 
 #endif  // _PRST_BLE_H_
\ No newline at end of file