diff --git a/lib/uart.c b/lib/uart.c
index 946e531..18c58c0 100644
--- a/lib/uart.c
+++ b/lib/uart.c
@@ -12,7 +12,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
-/** library for UART communication (code)
+/** library for UART communication
  *  @file
  *  @author King Kévin <kingkevin@cuvoodoo.info>
  *  @date 2016-2020
@@ -44,8 +44,8 @@
 
 /* output ring buffer, indexes, and available memory */
 static volatile uint8_t tx_buffer[64] = {0}; /**< ring buffer for data to transmit */
-static volatile uint8_t tx_i = 0; /**< current position of transmitted data */
-static volatile uint8_t tx_used = 0; /**< how much data needs to be transmitted */
+static volatile uint16_t tx_i = 0; /**< current position of transmitted data */
+static volatile uint16_t tx_used = 0; /**< how much data needs to be transmitted */
 
 void uart_setup(void)
 {
diff --git a/lib/uart.h b/lib/uart.h
index 59e0bf3..3e4f5ce 100644
--- a/lib/uart.h
+++ b/lib/uart.h
@@ -12,7 +12,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
-/** library for UART communication (API)
+/** library for UART communication
  *  @file
  *  @author King Kévin <kingkevin@cuvoodoo.info>
  *  @date 2016-2020