From 34a615bee174d0e0d2fb6911e8a84d11cd63ee26 Mon Sep 17 00:00:00 2001
From: Erich Eckner <git@eckner.net>
Date: Fri, 9 Oct 2020 14:09:37 +0200
Subject: sensor.c: do not accept all-zero as valid

---
 sensor.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sensor.c b/sensor.c
index 706817e..ca1f52d 100644
--- a/sensor.c
+++ b/sensor.c
@@ -39,7 +39,7 @@ int main() {
 	char data[5];
 	memset(&data[0], 0, 5);
 	int trials = 3;
-	while ((bit != 40) || ((data[0]+data[1]+data[2]+data[3]-data[4]) % 255 != 0)) {
+	while ((bit != 40) || ((data[0]+data[1]+data[2]+data[3]-data[4]) % 255 != 0) || ((data[0]|data[1]|data[2]|data[3]|data[4]) == 0)) {
 		trials--;
 		if (trials <= 0) {
 			fprintf(stderr, "Failed to obtain valid reading within 3 trials.\n");
-- 
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