CRC5 creation method and example.

[ldong.1]

Hi. I'm working with L9369 H-bridge driver and i want to know how to calculate CRC code in C programming.

it's polynomial is X^5+X^2+1 and initial value is 0x1F(1 1111)

1. Do you have any documentation regarding CRC implementation in C code?

i got CRC documentable attched document, but i think it's 26 bit and responding CRC value is not matched.

2.i want to know X^5+X^2+1 polynomial's CRC Lookup Table and how to use lookup table in C code. i calculated it by manual, and have some result. i want to know i calculate it correctly.

0->0x0

1-> 0x5

2->0xa

3->0xf

4->0x14

5->0x11

.....

255-> 0x14 

3. i want to know how to use lookup table below 2 cases. and sample code.

when i try to calucate CRC value with lookup-table, it's result is different to the value calculated by manual.

(please let me know how to calculate in case of CRC initial(0x1F) value apply, not apply case)

0x1234 ( 0001 0010 0011 0100)

0x2D40CFF(0010 1101 0100 0000 1100 1111 1111)

4. I attached excel file that i calculate CRC value by manual.

atttched document says 26 bit stream is  "0 0000:0011 0 0000:0000:0000:0000" and CRC value is 0x0B. My CRC value is 0x15(with initial CRC), 0x1A(with out initial CRC)

i don't know why the result is different to me. please help to solve it.

thank you.

thank you.

[Tesla DeLorean]

Prior thread https://community.st.com/s/question/0D53W00001gxfOrSAI/reqeust-for-l9369-crc-calculation-documentation

TX: [0 0000:0011 0 0 0000:0000:0000:0000 01011]
0180000B (32) [0B]
CRC:0B -> 0180000B
 
TX: [0 0000:0010 0 1 0000:0000:0000:0000 11110]
0120001E (32) [1E]
CRC:1E -> 0120001E
 
TX: [0 0000:0100 0 0 0000:0000:0000:0000 01111]
0200000F (32) [0F]
CRC:0F -> 0200000F
 
0 10 0000:0011 0000:0101:0111:0000 0:1111
4060AE0F (32) [0F]
CRC:0F -> 4060AE0F
 
RX: [0 00 0000:0000 0000:0000:0000:0000 10001]
00000011 (32) [11]
CRC:11 -> 00000011
 
RX: [0 10 0000:0011 0000:0101:0111:0000 01111]
4060AE0F (32) [0F]
CRC:0F -> 4060AE0F
 
RX: [0 00 0000:0010 0000:1001:0011:0011 01111] Table 6c, seems inconsistent
0041266F (32) [0F]
CRC:0A -> 0041266A
 
RX: [0 00 0000:0011 0000:0101:0111:0000 00110]
0060AE06 (32) [06]
CRC:06 -> 0060AE06
 
RX: [1000:1000:1111:1111:1111:1111:1111:0010]
88FFFFF2 (32) [12]
CRC:12 -> 88FFFFF2
 
RX: [0 00 1111:1101 0000:0001:0001:1111 00000]
1FA023E0 (32) [00]
CRC:00 -> 1FA023E0
 
RX: [0 00 0000:0011 0000:0101:0111:0000 00110]
0060AE06 (32) [06]
CRC:06 -> 0060AE06

[ldong.1]

hello. thank for reply. i'm modifying your example code for calculate data input with polynomial '100101', it's hard to implement. please help me to make getting CRC code function.

and i calculated your example, it seem that CRC code is wrong.

please check belows.

1. i calculated first Tx message's CRC, but i can't get CRC 0x01011 with initial value 0x1F. i think this example don't care CRC initial value.

TX: [0 0000:0011 0 0 0000:0000:0000:0000 01011]

-> payload is 0x60000, CRC is 0x0B(without initial value)

2.i calculated sencond Tx Message

TX: [0 0000:0010 0 1 0000:0000:0000:0000 11110]

->payload is 0x40000, CRC is 0x0F(without initial value)

[Tesla DeLorean]

Table 9 test values seem good

Table 9
TX: [0 1001:0000 0 0 0000:0000:0000:0000 01111]
4800000F (32) [0F]
CRC:0F -> 4800000F
 
RX: [0 00 0000:0000 0000:0000:0000:0000 10001]
00000011 (32) [11]
CRC:11 -> 00000011
 
TX: [0 0000:0011 0 1 0000:0000:0000:0000 01011]
01A0000B (32) [0B]
CRC:0B -> 01A0000B
 
RX: [1000:0000:1111:1111:1111:1111:1110:0101]
80FFFFE5 (32) [05]
CRC:05 -> 80FFFFE5
 
TX: [0 0000:0011 0 0 0000:0000:0000:0000 01011]
0180000B (32) [0B]
CRC:0B -> 0180000B
 
RX: [0 00 0000:0011 0000:0101:0111:0010 01100]
0060AE4C (32) [0C]
CRC:0C -> 0060AE4C
 
TX: [0 0000:0011 0 0 0000:0000:0000:0000 01011]
0180000B (32) [0B]
CRC:0B -> 0180000B
 
RX: [0 10 0000:0011 0000:0101:0111:0010 00101]
4060AE45 (32) [05]
CRC:05 -> 4060AE45
 
TX: [0 1111:1101 0 1 0000:0000:0000:0000 00000]
7EA00000 (32) [00]
CRC:00 -> 7EA00000
 
RX: [0 00 0000:0011 0000:0101:0111:0000 00110]
0060AE06 (32) [06]
CRC:06 -> 0060AE06
 
TX: [0 0000:0011 0 0 0000:0000:0000:0000 01011]
0180000B (32) [0B]
CRC:0B -> 0180000B
 
RX: [0 00 1111:1101 0000:0000:0001:1111 11100]
1FA003FC (32) [1C]
CRC:1C -> 1FA003FC