diff --git a/components/max7219/max7219.c b/components/max7219/max7219.c
index fd8939c..5a59893 100644
--- a/components/max7219/max7219.c
+++ b/components/max7219/max7219.c
@@ -236,7 +236,7 @@ esp_err_t max7219_draw_text_7seg(max7219_t *dev, uint8_t pos, const char *s)
 {
     CHECK_ARG(dev && s);
 
-    while (s && pos < dev->digits)
+    while (*s != '\0' && pos < dev->digits)
     {
         uint8_t c = get_char(dev, *s);
         if (*(s + 1) == '.')