diff --git a/tests/periph_uart_int/main.c b/tests/periph_uart_int/main.c
index 3fb22cb86c..65094e210d 100644
--- a/tests/periph_uart_int/main.c
+++ b/tests/periph_uart_int/main.c
@@ -28,6 +28,8 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <stdint.h>
+#include <inttypes.h>
 
 #include "cpu.h"
 #include "msg.h"
@@ -85,7 +87,7 @@ void *uart_thread(void *arg)
         ringbuffer_add(&tx_buf, status, strlen(status));
         uart_tx_begin(DEV);
 
-        vtimer_usleep(2000 * 1000);
+        vtimer_usleep(2000ul * 1000ul);
     }
 
     return 0;
@@ -101,7 +103,7 @@ int main(void)
     ringbuffer_init(&rx_buf, rx_mem, 128);
     ringbuffer_init(&tx_buf, tx_mem, 128);
 
-    printf("Initializing UART @ %i", BAUD);
+    printf("Initializing UART @ %" PRIu32, (uint32_t)BAUD);
     if (uart_init(DEV, BAUD, rx, tx, 0) >= 0) {
         puts("   ...done");
     }