我正在研究由红外遥控器控制的松下交流装置。遥控器发送12 bytes 。
前5 bytes始终相同。以下6 bytes对应于我自己能够弄清楚的空调温度，风扇，功能和其他选项。
最后一个byte是从第一个11 bytes(或从字节6到11(以某种方式获得的校验和
由于我在运行时重新创建 IR 代码，因此我需要能够计算这些数据包的校验和。 我尝试了许多标准的校验和算法，但没有一个给出有意义的结果。
你能帮我找出用于此设备的校验和功能吗？
以下是数据包列表，由标头+数据的11 bytes和校验和的1 byte组成，我能够从设备捕获这些数据包：
40 00 14 81 25 00 A0 65 00 00 00 26
40 00 14 81 25 00 A0 68 00 00 07 30
40 00 14 81 25 04 28 65 00 00 00 2A
40 00 14 81 25 04 28 68 00 00 00 2D
40 00 14 81 25 04 28 68 00 00 02 2F
40 00 14 81 25 04 28 68 00 00 03 30
40 00 14 81 25 04 28 68 00 00 04 31
40 00 14 81 25 04 28 68 00 00 05 32
40 00 14 81 25 04 28 68 00 00 07 34
40 00 14 81 25 04 28 69 00 00 01 2F
40 00 14 81 25 04 A0 68 00 00 07 34
40 00 14 81 25 08 9A 68 00 00 07 41
40 00 14 81 25 08 9C 68 00 00 07 43
40 00 14 81 25 08 9E 68 00 00 07 45
40 00 14 81 25 08 A0 68 00 00 00 31
40 00 14 81 25 08 A0 68 00 00 01 32
40 00 14 81 25 08 A0 68 00 00 02 33
40 00 14 81 25 08 A0 68 00 00 03 34
40 00 14 81 25 08 A0 68 00 00 07 38
40 00 14 81 25 08 A2 68 00 00 07 3A
40 00 14 81 25 08 A4 68 00 00 07 3C
40 00 14 81 25 08 A6 68 00 00 07 3E
40 00 14 81 25 08 A8 68 00 00 07 40
40 00 14 81 25 08 AA 68 00 00 07 42
40 00 14 81 25 08 AC 68 00 00 07 44
40 00 14 81 25 08 AE 68 00 00 07 46
40 00 14 81 25 09 A0 68 00 00 07 39
40 00 14 81 25 0A A0 68 00 00 07 3A
40 00 14 81 25 0C A0 68 00 00 07 3C
40 00 14 81 25 40 18 65 00 00 00 29
40 00 14 81 25 40 1A 65 00 00 00 2B
40 00 14 81 25 40 1C 65 00 00 00 2D
40 00 14 81 25 40 1E 65 00 00 00 2F
40 00 14 81 25 40 20 65 00 00 00 22
40 00 14 81 25 40 22 65 00 00 00 24
40 00 14 81 25 40 24 65 00 00 00 26
40 00 14 81 25 40 26 65 00 00 00 28
40 00 14 81 25 40 28 65 00 00 00 2A
40 00 14 81 25 40 2A 65 00 00 00 2C
40 00 14 81 25 40 2C 65 00 00 00 2E
40 00 14 81 25 40 2E 65 00 00 00 30
40 00 14 81 25 40 30 65 00 00 00 23
40 00 14 81 25 40 32 65 00 00 00 25
40 00 14 81 25 40 34 65 00 00 00 27
40 00 14 81 25 40 34 68 00 00 04 2E
40 00 14 81 25 80 1C 68 00 00 00 34
40 00 14 81 25 80 20 65 00 00 00 26
40 00 14 81 25 C0 20 65 00 00 00 2A
40 00 14 81 25 C0 28 68 00 00 02 37
我找到了一个与您的所有数据匹配的候选校验和函数，但我认为需要进一步调整，因为我怀疑我使用的幻数取决于我没有正确考虑的其他东西。
这是我能够进行逆向工程的功能：
uint8_t get_checksum(const uint8_t data[], const size_t size)
{
assert(data);
uint8_t checksum = 0;
for (size_t i = 0; i < size; ++i)
{
checksum += (data[i] >> 4) + (data[i] & 0x0f);
}
checksum -= 8; /* magic number */
return checksum;
};
替代版本：
uint8_t get_checksum(const uint8_t data[], const size_t size)
{
assert(data);
uint8_t checksum = 0xF8; /* magic number */
for (size_t i = 0; i < size; ++i)
{
checksum += (data[i] >> 4) + (data[i] & 0x0f);
}
return checksum;
};
例：
#include<stdio.h>
#include<stdint.h>
#include<assert.h>
uint8_t get_checksum(const uint8_t data[], const size_t size)
{
assert(data);
uint8_t checksum = 0xF8; /* magic number */
for (size_t i = 0; i < size; ++i)
{
checksum += (data[i] >> 4) + (data[i] & 0x0f);
}
return checksum;
};
int main ()
{
const size_t xlen = 49;
const size_t ylen = 12;
uint8_t v[49][12] = {
{0x40,0x00,0x14,0x81,0x25,0x00,0xA0,0x65,0x00,0x00,0x00,0x26},
{0x40,0x00,0x14,0x81,0x25,0x00,0xA0,0x68,0x00,0x00,0x07,0x30},
{0x40,0x00,0x14,0x81,0x25,0x04,0x28,0x65,0x00,0x00,0x00,0x2A},
{0x40,0x00,0x14,0x81,0x25,0x04,0x28,0x68,0x00,0x00,0x00,0x2D},
{0x40,0x00,0x14,0x81,0x25,0x04,0x28,0x68,0x00,0x00,0x02,0x2F},
{0x40,0x00,0x14,0x81,0x25,0x04,0x28,0x68,0x00,0x00,0x03,0x30},
{0x40,0x00,0x14,0x81,0x25,0x04,0x28,0x68,0x00,0x00,0x04,0x31},
{0x40,0x00,0x14,0x81,0x25,0x04,0x28,0x68,0x00,0x00,0x05,0x32},
{0x40,0x00,0x14,0x81,0x25,0x04,0x28,0x68,0x00,0x00,0x07,0x34},
{0x40,0x00,0x14,0x81,0x25,0x04,0x28,0x69,0x00,0x00,0x01,0x2F},
{0x40,0x00,0x14,0x81,0x25,0x04,0xA0,0x68,0x00,0x00,0x07,0x34},
{0x40,0x00,0x14,0x81,0x25,0x08,0x9A,0x68,0x00,0x00,0x07,0x41},
{0x40,0x00,0x14,0x81,0x25,0x08,0x9C,0x68,0x00,0x00,0x07,0x43},
{0x40,0x00,0x14,0x81,0x25,0x08,0x9E,0x68,0x00,0x00,0x07,0x45},
{0x40,0x00,0x14,0x81,0x25,0x08,0xA0,0x68,0x00,0x00,0x00,0x31},
{0x40,0x00,0x14,0x81,0x25,0x08,0xA0,0x68,0x00,0x00,0x01,0x32},
{0x40,0x00,0x14,0x81,0x25,0x08,0xA0,0x68,0x00,0x00,0x02,0x33},
{0x40,0x00,0x14,0x81,0x25,0x08,0xA0,0x68,0x00,0x00,0x03,0x34},
{0x40,0x00,0x14,0x81,0x25,0x08,0xA0,0x68,0x00,0x00,0x07,0x38},
{0x40,0x00,0x14,0x81,0x25,0x08,0xA2,0x68,0x00,0x00,0x07,0x3A},
{0x40,0x00,0x14,0x81,0x25,0x08,0xA4,0x68,0x00,0x00,0x07,0x3C},
{0x40,0x00,0x14,0x81,0x25,0x08,0xA6,0x68,0x00,0x00,0x07,0x3E},
{0x40,0x00,0x14,0x81,0x25,0x08,0xA8,0x68,0x00,0x00,0x07,0x40},
{0x40,0x00,0x14,0x81,0x25,0x08,0xAA,0x68,0x00,0x00,0x07,0x42},
{0x40,0x00,0x14,0x81,0x25,0x08,0xAC,0x68,0x00,0x00,0x07,0x44},
{0x40,0x00,0x14,0x81,0x25,0x08,0xAE,0x68,0x00,0x00,0x07,0x46},
{0x40,0x00,0x14,0x81,0x25,0x09,0xA0,0x68,0x00,0x00,0x07,0x39},
{0x40,0x00,0x14,0x81,0x25,0x0A,0xA0,0x68,0x00,0x00,0x07,0x3A},
{0x40,0x00,0x14,0x81,0x25,0x0C,0xA0,0x68,0x00,0x00,0x07,0x3C},
{0x40,0x00,0x14,0x81,0x25,0x40,0x18,0x65,0x00,0x00,0x00,0x29},
{0x40,0x00,0x14,0x81,0x25,0x40,0x1A,0x65,0x00,0x00,0x00,0x2B},
{0x40,0x00,0x14,0x81,0x25,0x40,0x1C,0x65,0x00,0x00,0x00,0x2D},
{0x40,0x00,0x14,0x81,0x25,0x40,0x1E,0x65,0x00,0x00,0x00,0x2F},
{0x40,0x00,0x14,0x81,0x25,0x40,0x20,0x65,0x00,0x00,0x00,0x22},
{0x40,0x00,0x14,0x81,0x25,0x40,0x22,0x65,0x00,0x00,0x00,0x24},
{0x40,0x00,0x14,0x81,0x25,0x40,0x24,0x65,0x00,0x00,0x00,0x26},
{0x40,0x00,0x14,0x81,0x25,0x40,0x26,0x65,0x00,0x00,0x00,0x28},
{0x40,0x00,0x14,0x81,0x25,0x40,0x28,0x65,0x00,0x00,0x00,0x2A},
{0x40,0x00,0x14,0x81,0x25,0x40,0x2A,0x65,0x00,0x00,0x00,0x2C},
{0x40,0x00,0x14,0x81,0x25,0x40,0x2C,0x65,0x00,0x00,0x00,0x2E},
{0x40,0x00,0x14,0x81,0x25,0x40,0x2E,0x65,0x00,0x00,0x00,0x30},
{0x40,0x00,0x14,0x81,0x25,0x40,0x30,0x65,0x00,0x00,0x00,0x23},
{0x40,0x00,0x14,0x81,0x25,0x40,0x32,0x65,0x00,0x00,0x00,0x25},
{0x40,0x00,0x14,0x81,0x25,0x40,0x34,0x65,0x00,0x00,0x00,0x27},
{0x40,0x00,0x14,0x81,0x25,0x40,0x34,0x68,0x00,0x00,0x04,0x2E},
{0x40,0x00,0x14,0x81,0x25,0x80,0x1C,0x68,0x00,0x00,0x00,0x34},
{0x40,0x00,0x14,0x81,0x25,0x80,0x20,0x65,0x00,0x00,0x00,0x26},
{0x40,0x00,0x14,0x81,0x25,0xC0,0x20,0x65,0x00,0x00,0x00,0x2A},
{0x40,0x00,0x14,0x81,0x25,0xC0,0x28,0x68,0x00,0x00,0x02,0x37}
};
// packet has 11 bytes, 1 byte is for the checksum
for (size_t i = 0; i < xlen; ++i)
{
uint8_t checksum = get_checksum(v[i], 11);
printf("result: %02x -- should be: %02x -- %sn",
checksum, v[i][ylen - 1],
(checksum - v[i][ylen - 1] == 0 ? "OK" : "ERROR"));
}
}
输出：
result: 26 -- should be: 26 -- OK
result: 30 -- should be: 30 -- OK
result: 2a -- should be: 2a -- OK
result: 2d -- should be: 2d -- OK
result: 2f -- should be: 2f -- OK
result: 30 -- should be: 30 -- OK
result: 31 -- should be: 31 -- OK
result: 32 -- should be: 32 -- OK
result: 34 -- should be: 34 -- OK
result: 2f -- should be: 2f -- OK
result: 34 -- should be: 34 -- OK
result: 41 -- should be: 41 -- OK
result: 43 -- should be: 43 -- OK
result: 45 -- should be: 45 -- OK
result: 31 -- should be: 31 -- OK
result: 32 -- should be: 32 -- OK
result: 33 -- should be: 33 -- OK
result: 34 -- should be: 34 -- OK
result: 38 -- should be: 38 -- OK
result: 3a -- should be: 3a -- OK
result: 3c -- should be: 3c -- OK
result: 3e -- should be: 3e -- OK
result: 40 -- should be: 40 -- OK
result: 42 -- should be: 42 -- OK
result: 44 -- should be: 44 -- OK
result: 46 -- should be: 46 -- OK
result: 39 -- should be: 39 -- OK
result: 3a -- should be: 3a -- OK
result: 3c -- should be: 3c -- OK
result: 29 -- should be: 29 -- OK
result: 2b -- should be: 2b -- OK
result: 2d -- should be: 2d -- OK
result: 2f -- should be: 2f -- OK
result: 22 -- should be: 22 -- OK
result: 24 -- should be: 24 -- OK
result: 26 -- should be: 26 -- OK
result: 28 -- should be: 28 -- OK
result: 2a -- should be: 2a -- OK
result: 2c -- should be: 2c -- OK
result: 2e -- should be: 2e -- OK
result: 30 -- should be: 30 -- OK
result: 23 -- should be: 23 -- OK
result: 25 -- should be: 25 -- OK
result: 27 -- should be: 27 -- OK
result: 2e -- should be: 2e -- OK
result: 34 -- should be: 34 -- OK
result: 26 -- should be: 26 -- OK
result: 2a -- should be: 2a -- OK
result: 37 -- should be: 37 -- OK