Add temperature to BM payload.

docs/payload.md

@@ -11,6 +11,7 @@
 | Altitude              |     0 - 65535     |   2 * 8 = 16   |
 
 This total length of the payload (without LoRaWAN header) is 10 bytes.
+All integers are big endian.
 
 
 ## Spreading Factor (SF)

src/app/benchmark/benchmark.h

@@ -13,6 +13,9 @@ This project is under the MIT license
 #include "lorariot.h"
 
 
+// Update temperature value every .. ms
+#define TEMPERATURE_UPDATE_MS  1500
+
 // Static payload for benchmark.
 extern lorariot_mcps_t bm_payload;
 

src/app/benchmark/payload.c

@@ -8,35 +8,76 @@ This project is under the MIT license
 */
 
 #include "benchmark.h"
+#include "drivers/gps.h"
+#include "drivers/ds75lx.h"
+
+#include <xtimer.h>
 
 
 // Buffer that contains encoded data.
-uint8_t bm_buffer[10];
+static uint8_t bm_buffer[10];
+
+// Temperature cache.
+static uint32_t temp_last_usec;
+static uint16_t temp_cache = 0;
 
 // Static payload for benchmark.
 lorariot_mcps_t bm_payload = LORARIOT_UNCONFIRMED_EX(DR_0, 50, 10, bm_buffer);
 
 
+// Get temperature with right payload format.
+static uint16_t bm_get_temperature(void)
+{
+    uint32_t now = xtimer_now_usec();
+    if (now - temp_last_usec < (TEMPERATURE_UPDATE_MS * 1000))
+        return temp_cache;
+
+    int16_t temp;
+    ds75_read_temperature(&temp);
+
+    temp_cache = temp;
+    temp_last_usec = now;
+
+    return (uint16_t)(temp + (55 << 8)) & 0x1FF;
+}
+
+
 // Encode message data to the payload.
 void bm_encode_payload(uint8_t power_i, uint8_t dr_i, uint8_t cr_i)
 {
+    // Retreive GPS data.
+    int32_t lat, lon; 
+    int16_t alt;
+    gps_get_binary(&lat, &lon, &alt);
+
+    // Retreive temperature.
+    uint16_t temp = bm_get_temperature();
+
+
     // Encode LoRa settings (on 8 bits).
     bm_buffer[0] = 
         ((dr_i    & 0b111)  << 5) |
         ((cr_i    & 0b1)    << 4) |
         ((power_i & 0b1111) << 0);
 
-    // Encode temperature (on 9 bits).
-    // TODO.
-
     // Encode latitude (on 23 bits, we assume it's > 0).
-    // TODO.
+    bm_buffer[2] = ((uint32_t)lat >> 16) & 0x7F;
+    bm_buffer[3] = ((uint32_t)lat >> 8)  & 0xFF;
+    bm_buffer[4] = ((uint32_t)lat >> 0)  & 0xFF;
 
     // Encode longitude (on 24 bits).
-    // TODO.
+    bm_buffer[5] = ((uint32_t)lon >> 16) & 0xFF;
+    bm_buffer[6] = ((uint32_t)lon >> 8)  & 0xFF;
+    bm_buffer[7] = ((uint32_t)lon >> 0)  & 0xFF;
+
+    // Encode temperature (on 9 bits).
+    bm_buffer[1] = (temp >> 1) & 0xFF;
+    bm_buffer[2] |= temp & 0b1;
 
     // Encode altitude (on 16 bits);
-    // TODO.
+    bm_buffer[8] = ((uint16_t)alt >> 8) & 0xFF;
+    bm_buffer[9] = ((uint16_t)alt >> 0) & 0xFF;
+
 
     // Change MCPS parameters for the next frame.
     bm_payload.code_rate = bm_cr[cr_i];

src/app/drivers/ds75lx.c

@@ -21,6 +21,14 @@ v1.0.
 // Masks to extract the concerned bits.
 #define MASK_RESOLUTION  0x60  // 0b01100000
 
+// Resolution encoding.
+static const uint8_t resoltions[] = {
+    0x00,  // DS75_RES9
+    0x20,  // DS75_RES10
+    0x40,  // DS75_RES11
+    0x60   // DS75_RES12
+};
+
 
 // Debug an I2C result.
 #define DS75_DEBUG(text, res)  \
@@ -49,7 +57,7 @@ uint8_t ds75_set_resolution(uint8_t resol)
     DS75_DEBUG("read config error", res);
 
     config &= ~MASK_RESOLUTION;
-    config |= resol;
+    config |= resoltions[resol];
 
     res = i2c_write_reg(DS75_I2C_DEV, DS75_I2C_ADDRESS, CONFIG_REG, DS75_RES9, 0);
     i2c_release(DS75_I2C_DEV);
@@ -60,7 +68,7 @@ uint8_t ds75_set_resolution(uint8_t resol)
 
 
 // Read temperature from DS75LX chip.
-uint8_t ds75_read_temperature(uint16_t *temp)
+uint8_t ds75_read_temperature(int16_t *temp)
 {
 	uint8_t buffer[2];
 

src/app/drivers/ds75lx.h

@@ -25,10 +25,10 @@ This project is under the MIT license
 
 
 // DS75LX resolution.
-#define DS75_RES9   0x00
-#define DS75_RES10  0x20
-#define DS75_RES11  0x40
-#define DS75_RES12  0x60
+#define DS75_RES9   0
+#define DS75_RES10  1
+#define DS75_RES11  2
+#define DS75_RES12  3
 
 
 /**
@@ -49,4 +49,4 @@ uint8_t ds75_set_resolution(uint8_t resol);
  * @param temp Where to store the result.
  * @return `DS75_SUCCESS` or I2C error code.
  */
-uint8_t ds75_read_temperature(uint16_t *temp);
+uint8_t ds75_read_temperature(int16_t *temp);