AP_IOMCU: added healthy API for use in arming checks

libraries/AP_IOMCU/AP_IOMCU.cpp

@@ -658,6 +658,7 @@ bool AP_IOMCU::check_crc(void)
     if (read_registers(PAGE_SETUP, PAGE_REG_SETUP_CRC, 2, (uint16_t *)&io_crc) &&
         io_crc == crc) {
         hal.console->printf("IOMCU: CRC ok\n");
+        crc_is_ok = true;
         return true;
     }
 
@@ -669,4 +670,13 @@ bool AP_IOMCU::check_crc(void)
     return false;
 }
 
+/*
+  check that IO is healthy. This should be used in arming checks
+ */
+bool AP_IOMCU::healthy(void)
+{
+    // for now just check CRC
+    return crc_is_ok;
+}
+
 #endif // HAL_WITH_IO_MCU

libraries/AP_IOMCU/AP_IOMCU.h

@@ -75,6 +75,9 @@ public:
     // set to oneshot mode
     void set_oneshot_mode(void);
 
+    // check if IO is healthy
+    bool healthy(void);
+
 private:
     AP_HAL::UARTDriver &uart;
 
@@ -195,6 +198,8 @@ private:
 
     bool corked;
 
+    bool crc_is_ok;
+
     // firmware upload
     const char *fw_name = "io_firmware.bin";
     const uint8_t *fw;

libraries/AP_IOMCU/fw_uploader.cpp

@@ -436,6 +436,9 @@ bool AP_IOMCU::verify_rev3(uint32_t fw_size_local)
         debug("CRC wrong: received: 0x%x, expected: 0x%x", (unsigned)crc, (unsigned)sum);
         return false;
     }
+
+    crc_is_ok = true;
+    
     return true;
 }