From 86e289f56f38dc7e59cf60b3d6f7cb349903dfb1 Mon Sep 17 00:00:00 2001
From: Marcel Peterkau <marcel@peterkau.de>
Date: Tue, 8 Mar 2022 21:23:27 +0100
Subject: [PATCH] improved crc

---
 Software/ChainLube/src/config.cpp | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/Software/ChainLube/src/config.cpp b/Software/ChainLube/src/config.cpp
index 44883ba..dd0e3c9 100644
--- a/Software/ChainLube/src/config.cpp
+++ b/Software/ChainLube/src/config.cpp
@@ -172,14 +172,19 @@ uint32_t Checksum_EEPROM(uint8_t const *data, size_t len)
 {
   if (data == NULL)
     return 0;
-  uint32_t crc = 0;
+  uint32_t crc, mask;
+  crc = 0xFFFFFFFF;
+
   while (len--)
   {
     crc ^= *data++;
     for (uint8_t k = 0; k < 8; k++)
-      crc = crc & 1 ? (crc >> 1) ^ 0xb2 : crc >> 1;
+    {
+      mask = -(crc & 1);
+      crc = (crc >> 1) ^ (0xEDB88320 & mask);
+    }
   }
-  return crc ^ 0xff;
+  return ~crc;
 }
 
 void dumpEEPROM(uint16_t memoryAddress, uint16_t length)