Add FLYSKY IBUS support

Inc/config.h

@@ -133,6 +133,21 @@
   // #define DEBUG_SERIAL_USART3                        // right sensor board cable, disable if I2C (nunchuck or lcd) is used!
 #endif
 
+#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
+#endif
+
+
 #if defined(FEEDBACK_SERIAL_USART2) || defined(DEBUG_SERIAL_USART2)
   #define UART_DMA_CHANNEL DMA1_Channel7
 #endif
@@ -317,7 +332,7 @@
 
 // ############################### VALIDATE SETTINGS ###############################
 
-#if !defined(VARIANT_ADC) && !defined(VARIANT_USART3) && !defined(VARIANT_HOVERCAR) && !defined(VARIANT_TRANSPOTTER) && !defined(VARIANT_NUNCHUCK) && !defined(VARIANT_PPM)
+#if !defined(VARIANT_ADC) && !defined(VARIANT_USART3) && !defined(VARIANT_HOVERCAR) && !defined(VARIANT_TRANSPOTTER) && !defined(VARIANT_NUNCHUCK) && !defined(VARIANT_PPM)&& !defined(VARIANT_IBUS)
   #error Variant not defined! Please check platformio.ini or Inc/config.h for available variants.
 #endif
 

Src/main.c

@@ -106,12 +106,25 @@ static int16_t timeoutCntADC   = 0;  // Timeout counter for ADC Protection
 static uint8_t timeoutFlagADC  = 0;  // Timeout Flag for for ADC Protection: 0 = OK, 1 = Problem detected (line disconnected or wrong ADC data)
 
 #if defined(CONTROL_SERIAL_USART2) || defined(CONTROL_SERIAL_USART3)
+  #ifdef CONTROL_IBUS
+    static uint16_t ibus_chksum;
+    static uint16_t ibus_captured_value[IBUS_NUM_CHANNELS];
+    
+    typedef struct{
+      uint8_t  start;
+      uint8_t  type; 
+      uint8_t  channels[IBUS_NUM_CHANNELS*2];
+      uint8_t  checksuml;
+      uint8_t  checksumh;    
+    } Serialcommand;
+  #elif
     typedef struct{
       uint16_t  start; 
       int16_t   steer;
       int16_t   speed;
       uint16_t  checksum;    
     } Serialcommand;
+  #endif
 static volatile Serialcommand command;
 static int16_t timeoutCntSerial   = 0;  // Timeout counter for Rx Serial command
 #endif
@@ -510,13 +523,29 @@ int main(void) {
     #if defined CONTROL_SERIAL_USART2 || defined CONTROL_SERIAL_USART3
 
       // 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 ++) {
+        ibus_chksum -= command.channels[i];
+      }
+      if (command.start == IBUS_LENGTH && command.type == IBUS_COMMAND && ibus_chksum == ( command.checksumh << 8) + command.checksuml ) {
+      #elif
       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) {
+            ibus_captured_value[(i/2)] = CLAMP( command.channels[i] + (command.channels[i+1] << 8) - 1000, INPUT_MIN, INPUT_MAX);
+          }
+          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);
+          #elif
           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         
         }

platformio.ini

@@ -13,6 +13,7 @@ src_dir     = Src
 ;default_envs = VARIANT_USART3      ; Variant for Serial control via USART3 input
 ;default_envs = VARIANT_NUNCHUCK    ; Variant for Nunchuck controlled vehicle build
 ;default_envs = VARIANT_PPM         ; Variant for RC-Remotes with PPM-Sum signal
+;default_envs = VARIANT_IBUS        ; Variant for RC-Remotes with FLYSKY IBUS
 ;default_envs = VARIANT_HOVERCAR    ; Variant for HOVERCAR build
 ;default_envs = VARIANT_TRANSPOTTER ; Variant for TRANSPOTTER build https://github.com/NiklasFauth/hoverboard-firmware-hack/wiki/Build-Instruction:-TranspOtter https://hackaday.io/project/161891-transpotter-ng
 ;================================================================
@@ -111,6 +112,27 @@ build_flags =
 
 ;================================================================
 
+[env:VARIANT_IBUS]
+platform        = ststm32
+framework       = stm32cube
+board           = genericSTM32F103RC
+debug_tool      = stlink
+upload_protocol = stlink
+
+build_flags =
+    -I${PROJECT_DIR}/inc/
+    -DUSE_HAL_DRIVER
+    -DSTM32F103xE
+    -Wl,-T./STM32F103RCTx_FLASH.ld
+    -Wl,-lc
+    -Wl,-lm
+    -g -ggdb        ; to generate correctly the 'firmware.elf' for STM STUDIO vizualization
+#    -Wl,-lnosys
+    -D VARIANT_IBUS
+    -D PALTFORMIO
+
+;================================================================
+
 [env:VARIANT_HOVERCAR]
 platform        = ststm32
 framework       = stm32cube