(Bonus 5) GD32L233 Review - CRC (with the clearest article explaining CRC in history)

韵湖葱白

(Bonus 5) GD32L233 Review - CRC (with the clearest article explaining CRC in history) [Copy link]

## Introduction GD32L233 supports hardware CRC, which is awesome. Compared with GD32F450, it can support the calculation of 7/8/16/32-bit CRC checksums, not just 32-bit checksums. What are the benefits? Those who understand CRC know that the checksums of 0x34 and 0x00000034 are different. This is not only because the calculation results are different, but also because the **computational complexity** is not at the same level. ![CRC32 calculation process of 0x34 and 0x00000034](https://gitee.com/anyangchina/embp/raw/master/20220125_CRC0x34计算.jpg) It is said that the annual salary of those who can understand this diagram can only reach one million. -_- I once wrote an article explaining CRC, you can take a look: [The clearest article explaining CRC in history](https://mp.weixin.qq.com/s/DbAdErPmk6dv_nS_w6-ASQ) Online CRC website: [Online CRC](http://www.ip33.com/crc.html) --- The CRC of GD32L233 is CRC32. - The corresponding standard is: CRC32/MPEG-2 - The polynomial is: x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x + 1, that is: 0x04C11DB7 - The initial value is: 0xFFFFFFFF - Input data inversion: false - Output data inversion: false - The resulting XOR value is: 0x00000000 This is not written in the official user manual, it is recommended that the official add it. ## Code Since GD32L233 supports CRC codes of different bits, its interface is different: ``` uint32_t crc_single_data_calculate(uint32_t sdata, uint8_t data_format) ``` GD32F450 is: ``` uint32_t crc_single_data_calculate(uint32_t sdata) ``` Note: **After each crc calculation, you need to call `crc_data_register_reset` to reset the register. ** The test process is relatively simple: ``` static void crc_test(void) { #ifdef CRC_TEST uint32_t data = 0xabcd1234; #if defined(GD32) || defined(STM32) uint32_t crc_data = crc_single_data_calculate(data); crc_data_register_reset(); #endif #if defined(GD32M0) uint3 2_t crc_data[3]; crc_data[0] = crc_single_data_calculate(data, INPUT_FORMAT_WORD); crc_data_register_reset(); crc_data[1] = crc_single_data_calculate(data, INPUT_FORMAT_HALFWORD); crc_data_register_reset(); crc_data[2] = crc_single_data_calculate(data, INPUT_FORMAT_BYTE); crc_data_register_reset(); #endif #ifdef STM32 printf("STM32: crc32 of 0x%X = 0x%X\r\n", data, crc_data); #endif #if defined(GD32) printf("GD32: crc32 of 0x%X = 0x %X\r\n", data, crc_data); #endif #if defined(GD32M0) printf("GD32: crc32 of 0x%X = [32]0x%X [16]0x%X [8]0x%X\r\n", data, crc_data[0], crc_data[1], crc_data[2]); #endif #endif } ```` Comparison of calculation results with different digits : data | CRC ---|--- 34 | 893EA4F8 1234 | 77227A2D ABCD1234 | F7018A40 00000034 | 0032C637 ## The test result is printed once a second. ![CRC test result](https://gitee.com/anyangchina/embp/raw/master/20220125_CRC test result.gif) ![](https://gitee.com/anyangchina/ppp/raw/master/文章EOF.gif) ![](https://gitee.com/anyangchina/ppp/raw/master/一扣三连.gif)

Jacktang

I have read it, and the introduction and explanation of CRC is indeed quite clear.

lugl4313820

What did you use to record the screen? Can you teach me? Thank you

韵湖葱白

lugl4313820 posted on 2022-1-26 07:48 What did you use to record the screen, OP? Can you teach me? Thank you

The screen recording software is this: https://www.apowersoft.cn/free-online-screen-recorder

Then save it as a gif

韵湖葱白

List of all review articles:

(Bonus 5) GD32L233 Review - CRC (with the clearest article explaining CRC in history) [Copy link]

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