diff --git a/include/can.h b/include/can.h
index e0a075b..aa2ae3a 100644
--- a/include/can.h
+++ b/include/can.h
@@ -50,5 +50,15 @@ bool can_is_rx_pending(can_data_t *hcan);
 
 bool can_send(can_data_t *hcan, struct gs_host_frame *frame);
 
+/** return CAN->ESR register which contains tx/rx error counters and
+ * LEC (last error code).
+ */
 uint32_t can_get_error_status(can_data_t *hcan);
+
+#define CAN_ERRCOUNT_THRESHOLD 15	/* send an error frame if tx/rx counters increase by more than this amount */
+
+/** parse status value returned by can_get_error_status().
+ * @param frame : will hold the generated error frame
+ * @return 1 when status changes (if any) need a new error frame sent
+ */
 bool can_parse_error_status(uint32_t err, uint32_t last_err, can_data_t *hcan, struct gs_host_frame *frame);
diff --git a/src/can.c b/src/can.c
index d866a7e..80c0a54 100644
--- a/src/can.c
+++ b/src/can.c
@@ -290,10 +290,10 @@ bool can_parse_error_status(uint32_t err, uint32_t last_err, can_data_t *hcan, s
 		should_send = true;
 	}
 	/* If either error counter increased by 15. */
-	if (((int)last_tx_error_cnt + 15) < tx_error_cnt) {
+	if (((int)last_tx_error_cnt + CAN_ERRCOUNT_THRESHOLD) < tx_error_cnt) {
 		should_send = true;
 	}
-	if (((int)last_rx_error_cnt + 15) < rx_error_cnt) {
+	if (((int)last_rx_error_cnt + CAN_ERRCOUNT_THRESHOLD) < rx_error_cnt) {
 		should_send = true;
 	}