diff --git a/docs/AHT20.pdf b/docs/AHT20.pdf
new file mode 100755
index 0000000..3728347
Binary files /dev/null and b/docs/AHT20.pdf differ
diff --git a/docs/BMP280.pdf b/docs/BMP280.pdf
new file mode 100755
index 0000000..f9f37f0
Binary files /dev/null and b/docs/BMP280.pdf differ
diff --git a/src/common/common.c b/src/common/common.c
index 1e2cfaa..900f49b 100644
--- a/src/common/common.c
+++ b/src/common/common.c
@@ -4,7 +4,7 @@
 
 static void Puts(const char *str)
 {
-	while (*str) {
+	while (*str != '\0') {
 		USART_Putc(*str++);
 	}
 }