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projects:pic32mx_obd_evaluation_board [2017/01/25 17:47] admin [Calculating CRC checksum] |
projects:pic32mx_obd_evaluation_board [2019/08/20 18:33] admin [PIC32MX OBD Evaluation Board] |
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| ====== PIC32MX OBD Evaluation Board ====== | ====== PIC32MX OBD Evaluation Board ====== | ||
| - | {{:projects:dsc_5593_800x536.jpg?512 |}} | + | {{:projects:dsc_5593_800x536.jpg?356 |}} |
| ===== Requirements ===== | ===== Requirements ===== | ||
| ===== Basics of communication protocol ===== | ===== Basics of communication protocol ===== | ||
| Line 109: | Line 109: | ||
| </code> | </code> | ||
| where | where | ||
| - | ^ TYPE | 1b | s - CRC-CCITT calculated by software (Px ignored); h - CRC calculated by DMA module | | + | ^ TYPE | 1b | s - 16-bit CRC-CCITT calculated by software (only P4 used); d - CRC calculated by DMA module | |
| ^ P1 | 1b | 0 - input data not reflected (MSB first); ≠0 - input data reflected (LSB first) | | ^ P1 | 1b | 0 - input data not reflected (MSB first); ≠0 - input data reflected (LSB first) | | ||
| - | ^ P2 | 1b | length of CRC polynom (max 32) | | + | ^ P2 | 1b | length of CRC polynom (1..32) | |
| ^ P3 | 4b | CRC polynom | | ^ P3 | 4b | CRC polynom | | ||
| ^ P4 | 4b | CRC seed | | ^ P4 | 4b | CRC seed | | ||
| Line 125: | Line 125: | ||
| ^ TIME | 2b | time in μs the calculation process took | | ^ TIME | 2b | time in μs the calculation process took | | ||
| Error codes | Error codes | ||
| - | ^ EINVAL | Invalid parameters provided | | + | ^ N02 | Invalid parameters provided | |
| ==== Configuring communication parameters ==== | ==== Configuring communication parameters ==== | ||
| <code> | <code> | ||
