uavcannode: Add CANNODE_TERM parameter (configure CAN termination on ARK cannodes)

- adds functionality to enable the built in can termination on the ARK cannodes

src/drivers/uavcannode/UavcanNode.cpp

@@ -513,6 +513,19 @@ extern "C" int uavcannode_start(int argc, char *argv[])
 	// Sarted byt the bootloader, we must pet it
 	watchdog_pet();
 
+#if defined(GPIO_CAN_TERM)
+	int32_t can_term = 0;
+	param_get(param_find("CANNODE_TERM"), &can_term);
+
+	if (can_term != 0) {
+		px4_arch_gpiowrite(GPIO_CAN_TERM, true);
+
+	} else {
+		px4_arch_gpiowrite(GPIO_CAN_TERM, false);
+	}
+
+#endif
+
 	// CAN bitrate
 	int32_t bitrate = 0;
 

src/drivers/uavcannode/uavcannode_params.c

@@ -50,3 +50,12 @@ PARAM_DEFINE_INT32(CANNODE_NODE_ID, 120);
  * @group UAVCAN
  */
 PARAM_DEFINE_INT32(CANNODE_BITRATE, 1000000);
+
+/**
+ * CAN built-in bus termination
+ *
+ * @boolean
+ * @max 1
+ * @group UAVCAN
+ */
+PARAM_DEFINE_INT32(CANNODE_TERM, 0);