finalizations and debugging

main/co2_sensor.c

@@ -28,12 +28,19 @@ static int mb_write_and_read(uint8_t *buffer, int num, size_t resplen) {
         return 0;
     }
 
+    // sometimes there's trash in the buffer, get rid of it
+    int discarded = 0;
+    uint8_t junk;
+    do {
+        discarded = uart_read_bytes(CO2_UART_NUM, &junk, 1, pdMS_TO_TICKS(2));
+    } while(discarded);
+
     ESP_LOGD(TAG, "Sending");
     ESP_LOG_BUFFER_HEXDUMP(TAG, buffer, num, ESP_LOG_DEBUG);
     uart_write_bytes(CO2_UART_NUM, buffer, num);
 
     ESP_LOGD(TAG, "Expect resp of %d bytes", resplen);
-    num = uart_read_bytes(CO2_UART_NUM, buffer, resplen, pdMS_TO_TICKS(500));
+    num = uart_read_bytes(CO2_UART_NUM, buffer, resplen, pdMS_TO_TICKS(TIMEOUT_MS));
     ESP_LOGD(TAG, "Received %d bytes", num);
     ESP_LOG_BUFFER_HEXDUMP(TAG, buffer, num, ESP_LOG_DEBUG);
 
@@ -54,7 +61,7 @@ static void write_saved_calib_to_sensor() {
 
         /* Write calib */
         resplen = 0;
-        num = mb_build_fc16(buffer, 128, &resplen, 104, 4, g_Settings.co2_calib, 5);
+        num = mb_build_fc16(buffer, 128, &resplen, CO2_ADDR, 4, g_Settings.co2_calib, 5);
         num = mb_write_and_read(buffer, num, resplen);
         resp = mb_parse_fc16(buffer, num);
         if (resp < 0) {
@@ -85,6 +92,8 @@ static bool ppm_looks_valid(uint16_t ppm) {
 void co2_read_task(void *param) {
     (void) param;
 
+    // 68 04 0a 00 00 00 00 00 00 03 b5 03 f2 dd c3
+
     vTaskDelay(pdMS_TO_TICKS(500));
 
     // TODO
@@ -97,7 +106,7 @@ void co2_read_task(void *param) {
 
     write_saved_calib_to_sensor();
 
-    const uint32_t read_cycle_time_ticks = 1000; //10 * 1000;
+    const uint32_t read_cycle_time_ticks = 10 * 1000;
     const uint32_t calib_persist_time_ticks = 12 * 3600 * 1000;
     _Static_assert(configTICK_RATE_HZ == 1000, "1kHz tick");
 
@@ -118,7 +127,7 @@ void co2_read_task(void *param) {
         }
 
         resplen = 0;
-        num = mb_build_fc4(buffer, 128, &resplen, 104, 0, 5);
+        num = mb_build_fc4(buffer, 128, &resplen, CO2_ADDR, 0, 5);
         num = mb_write_and_read(buffer, num, resplen);
         qty = mb_parse_fc4(buffer, num, values, 32);
         if (qty < 0) {
@@ -179,7 +188,10 @@ void co2_read_task(void *param) {
 
         if (!ppm_looks_valid(ppm)) {
             ESP_LOGW(TAG, "CO2 measures nonsense!");
-            co2_restart(true);
+            if (ppm != 0) {
+                // ppm=0 is OK, it means the ppm wasn't measured yet. just ignore it.
+                co2_restart(true);
+            }
         } else {
             // CO2 measurement looks OK
 
@@ -191,7 +203,7 @@ void co2_read_task(void *param) {
                 last_calib_persist = tickNow;
 
                 resplen = 0;
-                num = mb_build_fc3(buffer, 128, &resplen, 104, 4, 5);
+                num = mb_build_fc3(buffer, 128, &resplen, CO2_ADDR, 4, 5);
                 num = mb_write_and_read(buffer, num, resplen);
                 qty = mb_parse_fc3(buffer, num, values, 32);
                 if (qty < 0) {

main/modbus_fn.c

@@ -1,3 +1,6 @@
+
+//#define LOG_LOCAL_LEVEL ESP_LOG_DEBUG
+
 #include <assert.h>
 #include "modbus_fn.h"
 #include "modbus_crc.h"
@@ -9,6 +12,9 @@ static bool crc_matches(const uint8_t *buf, size_t len) {
     assert(buf);
     uint16_t real = modbus_crc(buf, len - 2);
     uint16_t given = ((uint16_t) buf[len - 2] << 8) | (uint16_t) buf[len - 1];
+    if (real != given) {
+        ESP_LOGE(TAG, "CRC computed of %d bytes: %04x, given %04x", len-2, real, given);
+    }
     return real == given;
 }