Updated IBUS variant

- separated the implementation from USART implementation for more clarity
- fixed warnings
- minor visual updates

Inc/config.h

@@ -10,6 +10,7 @@
   //#define VARIANT_USART3      // Variant for Serial control via USART3 input
   //#define VARIANT_NUNCHUCK    // Variant for Nunchuck controlled vehicle build
   //#define VARIANT_PPM         // Variant for RC-Remote with PPM-Sum Signal
+  //#define VARIANT_IBUS        // Variant for RC-Remotes with FLYSKY IBUS
   //#define VARIANT_HOVERCAR    // Variant for HOVERCAR build
   //#define VARIANT_TRANSPOTTER // Variant for TRANSPOTTER build https://github.com/NiklasFauth/hoverboard-firmware-hack/wiki/Build-Instruction:-TranspOtter https://hackaday.io/project/161891-transpotter-ng
 #endif
@@ -61,7 +62,7 @@
  * Then you can verify voltage on value 6 (to get calibrated voltage multiplied by 100).
  */
 #define BAT_FILT_COEF           655       // battery voltage filter coefficient in fixed-point. coef_fixedPoint = coef_floatingPoint * 2^16. In this case 655 = 0.01 * 2^16
-#define BAT_CALIB_REAL_VOLTAGE  3970      // input voltage measured by multimeter (multiplied by 100). In this case 43.00 V * 100 = 4300
+#define BAT_CALIB_REAL_VOLTAGE  3970      // input voltage measured by multimeter (multiplied by 100). For example 43.00 V * 100 = 4300
 #define BAT_CALIB_ADC           1492      // adc-value measured by mainboard (value nr 5 on UART debug output)
 
 #define BAT_CELLS               10        // battery number of cells. Normal Hoverboard battery: 10s
@@ -133,18 +134,18 @@
   // #define DEBUG_SERIAL_USART3                        // right sensor board cable, disable if I2C (nunchuck or lcd) is used!
 #endif
 
+// ###### CONTROL VIA RC REMOTE WITH FLYSKY IBUS PROTOCOL ######
+/* Connected to Left sensor board cable. Channel 1: steering, Channel 2: speed. */
 #ifdef VARIANT_IBUS     
-  // ###### CONTROL VIA RC REMOTE WITH FLYSKY IBUS PROTOCOL ######
-  // left sensor board cable. Channel 1: steering, Channel 2: speed.
   #define CONTROL_IBUS                                  // use IBUS as input
   #define IBUS_NUM_CHANNELS   14                        // total number of IBUS channels to receive, even if they are not used.
   #define IBUS_LENGTH         0x20
   #define IBUS_COMMAND        0x40
 
-  #define CONTROL_SERIAL_USART2                      // left sensor board cable, disable if ADC or PPM is used! For Arduino control check the hoverSerial.ino
-  #define FEEDBACK_SERIAL_USART2                     // left sensor board cable, disable if ADC or PPM is used!
   #undef  USART2_BAUD
   #define USART2_BAUD         115200
+  #define CONTROL_SERIAL_USART2                         // left sensor board cable, disable if ADC or PPM is used!
+  #define FEEDBACK_SERIAL_USART2                        // left sensor board cable, disable if ADC or PPM is used!
 #endif
 
 
@@ -156,8 +157,8 @@
   #define UART_DMA_CHANNEL DMA1_Channel2
 #endif
 
+// ###### CONTROL VIA RC REMOTE ######
 #ifdef VARIANT_PPM
-  // ###### CONTROL VIA RC REMOTE ######
   // left sensor board cable. Channel 1: steering, Channel 2: speed.
   #define CONTROL_PPM                 // use PPM-Sum as input. disable CONTROL_SERIAL_USART2!
   #define PPM_NUM_CHANNELS 6          // total number of PPM channels to receive, even if they are not used.

README.md

@@ -156,10 +156,11 @@ Most robust way for input is to use the ADC and potis. It works well even on 1m
 This firmware offers currently these variants (selectable in [platformio.ini](/platformio.ini) and / or [/Inc/config.h](/Inc/config.h)):
 - **VARIANT_ADC**: In this variant the motors are controlled by two potentiometers connected to the Left sensor cable (long wired)
 - **VARIANT_USART3**: In this variant the motors are controlled via serial protocol on USART3 right sensor cable (short wired). The commands can be sent from an Arduino. Check out the [hoverserial.ino](/02_Arduino/hoverserial) as an example sketch.
+- **VARIANT_NUNCHUCK**: Wii Nunchuck offers one hand control for throttle, braking and steering. This was one of the first input device used for electric armchairs or bottle crates.
+- **VARIANT_PPM**: This is when you want to use a RC remote control with PPM Sum signal
+- **VARIANT_IBUS**: This is when you want to use a RC remote control with Flysky IBUS protocol connected to the Left sensor cable.
 - **VARIANT_HOVERCAR**: In this variant the motors are controlled by two pedals brake and throttle. Reverse is engaged by double tapping on the brake pedal at standstill.
 - **VARIANT_TRANSPOTTER**: This build is for transpotter which is a hoverboard based transportation system. For more details on how to build it check [here](https://github.com/NiklasFauth/hoverboard-firmware-hack/wiki/Build-Instruction:-TranspOtter) and [here](https://hackaday.io/project/161891-transpotter-ng).
-- **VARIANT_NUNCHUCK**: Wii Nunchuck offers one hand control for throttle, braking and steering. This was one of the first input device used for electric armchairs or bottle crates.
-- **VARIANT_PPM**: This is when you want to use a RC remote control with PPM Sum singnal 
 
 Of course the firmware can be further customized for other needs or projects.
 

Src/control.c

@@ -112,8 +112,6 @@ void Nunchuck_Read(void) {
   HAL_Delay(3);
   if (HAL_I2C_Master_Receive(&hi2c2,0xA4,(uint8_t*)nunchuck_data, 6, 10) == HAL_OK) {
     timeout = 0;
-  } else {
-    timeout++;
   }
 
 #ifndef TRANSPOTTER

Src/main.c

@@ -145,7 +145,6 @@ typedef struct{
 } SerialFeedback;
 static SerialFeedback Feedback;
 #endif
-static uint8_t serialSendCnt;           // serial send counter
 
 #if defined(CONTROL_NUNCHUCK) || defined(SUPPORT_NUNCHUCK) || defined(CONTROL_PPM) || defined(CONTROL_ADC)
 static uint8_t button1, button2;
@@ -181,6 +180,7 @@ extern volatile uint32_t timeout;       // global variable for timeout
 extern int16_t batVoltage;              // global variable for battery voltage
 
 static uint32_t inactivity_timeout_counter;
+static uint32_t main_loop_counter;
 
 extern uint8_t nunchuck_data[6];
 #ifdef CONTROL_PPM
@@ -525,27 +525,41 @@ int main(void) {
       // Handle received data validity, timeout and fix out-of-sync if necessary
       #ifdef CONTROL_IBUS
         ibus_chksum = 0xFFFF - IBUS_LENGTH - IBUS_COMMAND;
-      for (uint8_t i = 0; i < (IBUS_NUM_CHANNELS * 2); i ++) {
+        for (uint8_t i = 0; i < (IBUS_NUM_CHANNELS * 2); i++) {
           ibus_chksum -= command.channels[i];
         }
-      if (command.start == IBUS_LENGTH && command.type == IBUS_COMMAND && ibus_chksum == ( command.checksumh << 8) + command.checksuml ) {
+        if (command.start == IBUS_LENGTH && command.type == IBUS_COMMAND && ibus_chksum == (uint16_t)((command.checksumh << 8) + command.checksuml)) {
-      #else
-      if (command.start == START_FRAME && command.checksum == (uint16_t)(command.start ^ command.steer ^ command.speed)) {
-      #endif   
           if (timeoutFlagSerial) {                      // Check for previous timeout flag  
             if (timeoutCntSerial-- <= 0)                // Timeout de-qualification
               timeoutFlagSerial = 0;                    // Timeout flag cleared           
           } else {         
-          #ifdef CONTROL_IBUS
+            for (uint8_t i = 0; i < (IBUS_NUM_CHANNELS * 2); i+=2) {
-          for (uint8_t i = 0; i < (IBUS_NUM_CHANNELS * 2); i +=2) {
+              ibus_captured_value[(i/2)] = CLAMP(command.channels[i] + (command.channels[i+1] << 8) - 1000, 0, INPUT_MAX); // 1000-2000 -> 0-1000
-            ibus_captured_value[(i/2)] = CLAMP( command.channels[i] + (command.channels[i+1] << 8) - 1000, 0, INPUT_MAX); // 1000-2000 -> 0-1000
             }
             cmd1              = CLAMP((ibus_captured_value[0] - INPUT_MID) * 2, INPUT_MIN, INPUT_MAX);
             cmd2              = CLAMP((ibus_captured_value[1] - INPUT_MID) * 2, INPUT_MIN, INPUT_MAX);
+            command.start     = 0xFF;                   // Change the Start Frame for timeout detection in the next cycle
+            timeoutCntSerial  = 0;                      // Reset the timeout counter
+          }
+        } else {
+          if (timeoutCntSerial++ >= SERIAL_TIMEOUT) {   // Timeout qualification
+            timeoutFlagSerial = 1;                      // Timeout detected
+            timeoutCntSerial  = SERIAL_TIMEOUT;         // Limit timout counter value
+          }
+          // Check periodically the received Start Frame. If it is NOT OK, most probably we are out-of-sync. Try to re-sync by reseting the DMA
+          if (main_loop_counter % 25 == 0 && command.start != IBUS_LENGTH && command.start != 0xFF) {
+            HAL_UART_DMAStop(&huart);                
+            HAL_UART_Receive_DMA(&huart, (uint8_t *)&command, sizeof(command));
+          }
+        }  
       #else
+        if (command.start == START_FRAME && command.checksum == (uint16_t)(command.start ^ command.steer ^ command.speed)) {
+          if (timeoutFlagSerial) {                      // Check for previous timeout flag  
+            if (timeoutCntSerial-- <= 0)                // Timeout de-qualification
+              timeoutFlagSerial = 0;                    // Timeout flag cleared           
+          } else {
             cmd1              = CLAMP((int16_t)command.steer, INPUT_MIN, INPUT_MAX);
             cmd2              = CLAMP((int16_t)command.speed, INPUT_MIN, INPUT_MAX);
-          #endif         
             command.start     = 0xFFFF;                 // Change the Start Frame for timeout detection in the next cycle
             timeoutCntSerial  = 0;                      // Reset the timeout counter         
           }
@@ -554,13 +568,13 @@ int main(void) {
             timeoutFlagSerial = 1;                      // Timeout detected
             timeoutCntSerial  = SERIAL_TIMEOUT;         // Limit timout counter value
           }
-        // Check the received Start Frame. If it is NOT OK, most probably we are out-of-sync.
+          // Check periodically the received Start Frame. If it is NOT OK, most probably we are out-of-sync. Try to re-sync by reseting the DMA
-        // Try to re-sync by reseting the DMA
+          if (main_loop_counter % 25 == 0 && command.start != START_FRAME && command.start != 0xFFFF) {
-        if (command.start != START_FRAME && command.start != 0xFFFF) {
             HAL_UART_DMAStop(&huart);                
             HAL_UART_Receive_DMA(&huart, (uint8_t *)&command, sizeof(command));
           }
         }
+      #endif     
 
       if (timeoutFlagSerial) {                          // In case of timeout bring the system to a Safe State
         ctrlModReq  = 0;                                // OPEN_MODE request. This will bring the motor power to 0 in a controlled way
@@ -746,9 +760,7 @@ int main(void) {
     board_temp_adcFilt  = (int16_t)(board_temp_adcFixdt >> 20);  // convert fixed-point to integer
     board_temp_deg_c    = (TEMP_CAL_HIGH_DEG_C - TEMP_CAL_LOW_DEG_C) * (board_temp_adcFilt - TEMP_CAL_LOW_ADC) / (TEMP_CAL_HIGH_ADC - TEMP_CAL_LOW_ADC) + TEMP_CAL_LOW_DEG_C;
 
-    serialSendCnt++;              // Increment the counter
+    if (main_loop_counter % 25 == 0) {    // Send data periodically
-    if (serialSendCnt > 20) {     // Send data every 100 ms = 20 * 5 ms, where 5 ms is approximately the main loop duration
-      serialSendCnt = 0;          // Reset the counter
 
       // ####### DEBUG SERIAL OUT #######
       #if defined(DEBUG_SERIAL_USART2) || defined(DEBUG_SERIAL_USART3)
@@ -837,6 +849,9 @@ int main(void) {
     if (inactivity_timeout_counter > (INACTIVITY_TIMEOUT * 60 * 1000) / (DELAY_IN_MAIN_LOOP + 1)) {  // rest of main loop needs maybe 1ms
       poweroff();
     }
+
+    main_loop_counter++;
+    timeout++;
   }
 }