diff --git a/src/utility.c b/src/utility.c
index 82c5b8b..3ad9f48 100644
--- a/src/utility.c
+++ b/src/utility.c
@@ -13,6 +13,16 @@ uint8_t bit_count(uint8_t b) {
 	return b;
 }
 
+uint16_t lfsr_update(void) {
+	static uint16_t lfsr = 0xF00D;
+	uint16_t bit;
+
+    bit = ((lfsr >> 0) ^ (lfsr >> 2) ^ (lfsr >> 3) ^ (lfsr >> 5)) & 1;
+    lfsr = (lfsr >> 1) | (bit << 15);
+
+    return lfsr;
+}
+
 // Note that the horizontal values here are in group of 7 pixels
 void clear_box(uint8_t w, uint8_t h, uint8_t off_x, uint8_t off_y, uint8_t *disp_buf) {
 	for(uint8_t y = off_y; y < off_y + h; y++) {
diff --git a/src/utility.h b/src/utility.h
index 7983bf4..5b97469 100644
--- a/src/utility.h
+++ b/src/utility.h
@@ -19,6 +19,7 @@
 #define ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0]))
 
 uint8_t bit_count(uint8_t b);
+uint16_t lfsr_update(void);
 void clear_box(uint8_t w, uint8_t h, uint8_t off_x, uint8_t off_y, uint8_t *disp_buf);
 void draw_pic(uint16_t w, uint8_t h, uint8_t off_x, uint8_t off_y, const uint8_t *data, uint8_t *disp_buf);
 void print_line(const char* line, uint8_t off_x, uint8_t off_y);