diff --git a/.gitignore b/.gitignore
index b678af8..47d4df6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,7 @@
 a.out
 *.o
 fake-values
-essai
+essai serail/t
 doc/*.toc doc/*.log doc/*.aux doc/*.pdf
 
 
diff --git a/serial/Makefile b/serial/Makefile
new file mode 100644
index 0000000..3af2ad8
--- /dev/null
+++ b/serial/Makefile
@@ -0,0 +1,9 @@
+
+
+
+serial.o:	serial.c serial.h Makefile
+	gcc -Wall -c $<
+
+t:	t.c serial.o Makefile
+	gcc -Wall  $< serial.o -o $@
+
diff --git a/serial/serial.c b/serial/serial.c
index d38f6c8..87dd3d9 100644
--- a/serial/serial.c
+++ b/serial/serial.c
@@ -96,3 +96,21 @@ tcsetattr(uart0, TCSANOW, &options);
 
 return uart0;
 }
+
+/* -------------------------------------------------------------------- */
+
+int getbyte(int fd)
+{
+unsigned char   byte;
+int             foo;
+
+foo = read(fd, &byte, 1);
+if (1 != foo)
+        {
+        perror("read a byte");
+        return -1;
+        }
+return (int)byte;
+}
+
+/* -------------------------------------------------------------------- */
diff --git a/serial/serial.h b/serial/serial.h
index bfec248..3bafcb5 100644
--- a/serial/serial.h
+++ b/serial/serial.h
@@ -4,3 +4,5 @@
 
 int prepare_UART(char *port, int bauds);
 
+int getbyte(int fd);
+
diff --git a/serial/t.c b/serial/t.c
new file mode 100644
index 0000000..b912596
--- /dev/null
+++ b/serial/t.c
@@ -0,0 +1,21 @@
+
+
+#include  <stdio.h>
+
+#include  "serial.h"
+
+int main (int argc, char *argv[])
+{
+int	serial_in;
+int	byte, foo;
+
+serial_in = prepare_UART("/dev/ttyS0", 9600);
+fprintf(stderr, "prepare uart -> %d\n", serial_in);
+
+for (foo=0; foo<20; foo++) {
+	byte = getbyte(serial_in);
+	printf("%6d    %02x\n", foo, byte);
+	}
+
+return 0;
+}