From f40daf62d4273d50cd1bad071c94e4ab1b2092c7 Mon Sep 17 00:00:00 2001
From: Soundflog <stud128097@vyatsu.ru>
Date: Tue, 25 Apr 2023 10:12:54 +0300
Subject: [PATCH] master with CRC8
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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доработать
---
 SPI/master/master.ino | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/SPI/master/master.ino b/SPI/master/master.ino
index 008dfab..0819cda 100644
--- a/SPI/master/master.ino
+++ b/SPI/master/master.ino
@@ -17,6 +17,7 @@ void SPI_MasterInit(void)
 }
 
 void Print(byte *data2, int lenght){
+  Serial.println("----");
   for(int i = 0; i < lenght; i++) {
     Serial.print(data2[i]);
     Serial.print(" ");
@@ -73,16 +74,27 @@ void setup()
 
 // Функция для вычисления контрольной суммы XOR
 byte calculateXORChecksum(byte *data, int length) {
-  byte checksum = 0;
-  for (int i = 0; i < length -1; i++) {
-    checksum ^= data[i];
+  byte crc = 0x00;
+  byte poly = 0x07; // полином для CRC8
+
+  for (int i = 0; i < length; i++) {
+      crc ^= data[i]; // XOR текущего байта с crc
+
+      for (int j = 0; j < length; j++) {
+          if (crc & 0x80) { // если старший бит crc равен 1
+              crc = (crc << 1) ^ poly; // сдвигаем crc на 1 бит влево и XOR с полиномом
+          } else {
+              crc <<= 1; // иначе просто сдвигаем на 1 бит влево
+          }
+      }
   }
-  return checksum;
+
+  return crc;
 }
 
 void loop()
 {
-    char data[5] = {6, 1, 3, 8, 0};
+    char data[8] = {6, 1, 3, 8, 8, 8, 8, 0};
     
     int length = sizeof(data);
 
@@ -91,27 +103,30 @@ void loop()
     byte checking = calculateXORChecksum(data, length); 
     int size = sizeof(data) / sizeof(data[0]);
     data[size - 1] = checking;
+    Print(data, size);
     // Serial.println(last);
     
     SPI_MasterTransmit(data, length);
     _delay_ms(1000);
 
-    char data2[5] = {6, 9, 7, 10, 0};
+    char data2[8] = {6, 9, 7, 10, 8, 8, 8, 0};
     int length2 = sizeof(data2);
     const int last2 = data2 [ (sizeof(data2) / sizeof(data2[0]))-1];
     byte checking2 = calculateXORChecksum(data2, length2); 
     int size2 = sizeof(data2) / sizeof(data2[0]);
     data2[size2 - 1] = checking2;
+    Print(data2, size2);
     SPI_MasterTransmit(data2, length2);    
 
     _delay_ms(1000);
 
-    char data3[5] = {6, 11, 12, 13, 0};
+    char data3[8] = {6, 11, 12, 13, 8, 8, 8, 0};
     int length3 = sizeof(data3);
     const int last3 = data3 [ (sizeof(data3) / sizeof(data3[0]))-1];
     byte checking3 = calculateXORChecksum(data3, length3); 
     int size3 = sizeof(data3) / sizeof(data3[0]);
     data3[size3 - 1] = checking3;
+    Print(data3, size3);
     SPI_MasterTransmit(data3, length3);    
 
     _delay_ms(1000);