Add CAN1 100 ms heartbeat with verified firmware and updated protocol PDF

firmware/Core/Inc/ami_protocol.h

@@ -15,6 +15,8 @@
 #define AMI_CAN_ID_BMS_EXTREMES_EXT 0x186140F3UL
 /* AMI task requests are not ASSI commands; no SDC mapping is defined. */
 #define AMI_CAN_ID_TASK_REQUEST     0x300U
+#define AMI_CAN_ID_HEARTBEAT        0x301U
+#define AMI_HEARTBEAT_PERIOD_MS      100U
 
 #define AMI_CAN_DATA_TIMEOUT_MS      500U
 #define AMI_ADC_TIMEOUT_MS          1500U

firmware/Core/Src/ami_app.c

@@ -537,6 +537,47 @@ static void SendPendingTask(void)
   }
 }
 
+static void SendHeartbeat(void)
+{
+  static uint32_t last_tx_ms;
+  static uint16_t sequence;
+  uint32_t now = HAL_GetTick();
+  FDCAN_TxHeaderTypeDef header = {0};
+  uint8_t data[8];
+
+  if ((uint32_t)(now - last_tx_ms) < AMI_HEARTBEAT_PERIOD_MS)
+  {
+    return;
+  }
+  /* Skip missed periods instead of generating a catch-up burst. */
+  last_tx_ms = now;
+  data[0] = 1U; /* Protocol version. */
+  data[1] = 0U; /* Reserved. */
+  data[2] = (uint8_t)sequence;
+  data[3] = (uint8_t)(sequence >> 8);
+  data[4] = (uint8_t)now;
+  data[5] = (uint8_t)(now >> 8);
+  data[6] = (uint8_t)(now >> 16);
+  data[7] = (uint8_t)(now >> 24);
+  ++sequence;
+
+  header.Identifier = AMI_CAN_ID_HEARTBEAT;
+  header.IdType = FDCAN_STANDARD_ID;
+  header.TxFrameType = FDCAN_DATA_FRAME;
+  header.DataLength = FDCAN_DLC_BYTES_8;
+  header.ErrorStateIndicator = FDCAN_ESI_ACTIVE;
+  header.BitRateSwitch = FDCAN_BRS_OFF;
+  header.FDFormat = FDCAN_CLASSIC_CAN;
+  header.TxEventFifoControl = FDCAN_NO_TX_EVENTS;
+
+  /* CAN1 (500 kbit/s) only; reserve one FIFO slot for task requests.
+     A busy port skips this period; no software backlog or blocking retry. */
+  if (HAL_FDCAN_GetTxFifoFreeLevel(&hfdcan1) > 1U)
+  {
+    (void)HAL_FDCAN_AddMessageToTxFifoQ(&hfdcan1, &header, data);
+  }
+}
+
 static void UpdateTimeoutsAndLeds(void)
 {
   static uint32_t last_heartbeat_ms;
@@ -720,6 +761,7 @@ void AMI_App_Service(void)
   uint32_t now = HAL_GetTick();
 
   SendPendingTask();
+  SendHeartbeat();
   UpdateTimeoutsAndLeds();
   /* The HMI may reboot/reconnect after the MCU has already sent its state. */
   if ((now - last_screen_sync_ms) >= AMI_SCREEN_RESYNC_MS)