The length of a packet (or a portion of it) can be calculated automatically,
by placing tokens. The length can include or exclude the checksum/CRC.
| Token | Function |
| <data> or [ | start of data for length calculation |
| </data> or ] | end of data for length calculation |
| <length> | length byte |
| <length_BE> | length word Big Endian |
| <length_LE> | length word Little Endian |
<data> and </data> are symbolic tokens. No bytes will be inserted at these locations.
<length*> are the place holders for the resulting data length.
They will occupy their respective size in the message (i.e. 1 or 2 bytes).
| Token | Function |
| <check> or { | start of data/select default check method for calculation |
| </check> or } | end of data for CRC or checksum calculation and place holder for result (by default) |
| <check-value> | place holder for result (overrides </check>) |
if the <check-value> token is used, the result will be inserted at the current location instead of the end specified by </check>.
The check method is selectable by the combo box in the menubar or can be specified when loading a string file.
To specify it at load time, put the specific CRC or checksum from the tables below without the <> and prefix it with %. Protocoltool will read this as a command line and will not load it into the entries. This will update the CRC combobox.
Ex.: for specifying CRC-32 (IEEE 802.3), put somewhere in the file the following line.
% crc-32
| Token | Name | Polynom |
| <crc-8-atm> | CRC-8 ATM | x8 + x2 + x + 1 (ATM HEC) |
| <crc-8-ccitt> | CRC-8 CCITT | x8 + x7 + x3 + x2 + 1 (1-Wire bus) |
| <crc-8-maxim> | CRC-8 DALLAS/MAXIM | x8 + x5 + x4 + 1 (1-Wire bus) |
| <crc-8> | CRC-8 | x8 + x7 + x6 + x4 + x2 + 1 |
| <crc-8-j1850> | CRC-8 SAE J1850 | x8 + x4 + x3 + x2 + 1 |
| <crc-8-wcdma> | CRC-8 WCDMA | x8 + x7 + x4 + x3 + x + 1 |
| <crc-8-itu> | CRC-8 ITU | x8 + x2 + x + 1 |
| <crc-8-rohc> | CRC-8 ROHC | x8 + x2 + x + 1 |
| <crc-8-darc> | CRC-8 DARC | x8 + x5 + x4 + x3 + 1 |
| <crc-8-icode> | CRC-8 I-CODE | x8 + x4 + x3 + x2 + 1 |
| Token | Name | Polynom |
| <crc-16> | CRC-16 | x16 + x15 + x2 + 1 |
| <crc-sick> | CRC-16 (Sick) | x16 + x15 + x2 + 1 |
| <crc-dnp> | CRC-DNP | x16 + x13 + x12 + x11 + x10 + x8 + x6 + x5 + x2 + 1 |
| <crc-modbus> | CRC-16 (Modbus) | x16 + x15 + x2 + 1 |
| <crc-ccitt-xmodem> | CRC-CCITT (XModem) | x16 + x12+ x5 + 1 |
| <crc-ccitt-kermit> | CRC-CCITT (Kermit) | x16 + x12+ x5 + 1 |
| <crc-ccitt-ffff> | CRC-CCITT (0xFFFF) | x16 + x12+ x5 + 1 |
| <crc-ccitt-1d0f> | CRC-CCITT (0x1D0F) | x16 + x12+ x5 + 1 |
| <crc-x25> | CRC16 X-25 | x16 + x12+ x5 + 1 |
| <crc-t10-dif> | CRC16 T10-DIF | x16 + x15 + x11 + x9 + x8 + x7 + x5 + x4 + x2 + x + 1 |
| <crc-dect-x> | CRC16 DECT-X | x16 + x10 + x8 + x7 + x3 + 1 |
| <crc-dect-r> | CRC16 DECT-R | x16 + x10 + x8 + x7 + x3 + 1 |
| <crc-buypass> | CRC16 BUYPASS | x16 + x15 + x2 + 1 |
| <crc-dds-110> | CRC16 DDS-110 | x16 + x15 + x2 + 1 |
| <crc-16-maxim> | CRC16 Maxim | x16 + x15 + x2 + 1 |
| <crc-usb> | CRC16 USB | x16 + x15 + x2 + 1 |
| <crc-genibus> | CRC16 Genibus | x16 + x12+ x5 + 1 |
| <crc-mcrf4xx> | CRC16 MCRF4XX | x16 + x12+ x5 + 1 |
| <crc-riello> | CRC16 Riello | x16 + x12+ x5 + 1 |
| <crc-en-13757> | CRC16 EN-13757 | x16 + x13 + x12 + x11 + x10 + x8 + x6 + x5 + x2 + 1 |
| <crc-teledisk> | CRC16 Teledisk | x16 + x15 + x13 + x7 + x4 + x2 + x1 + 1 |
| Token | Name | Polynom |
| <crc-24-flexray-a> | CRC-24 Flexray-A | x24 + x22 + x20 + x19 + x18 + x16 + x14 + x13 + x11 + x10 + x8 + x7 + x6 + x3 + x + 1 |
| <crc-24-flexray-b> | CRC-24 Flexray-B | same as above |
| <crc-24-r64> | CRC-24-R64/OpenPGP | x24 + x23 + x18 + x17 + x14 + x11 + x10 + x7 + x6 + x5 + x4 + x3 + x + 1 |
| Token | Name | Polynom |
| <crc-32> | CRC-32 (IEEE 802.3) | x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x + 1 |
| <crc-32-bzip2> | CRC32 BZIP2 | same as above |
| <crc-32-mpeg-2> | CRC32 MPEG_2 | same as above |
| <crc-32-posix> | CRC32 POSIX | same as above |
| <crc-32-jamcrc> | CRC32 JAMCRC | same as above |
| <crc-32-xfer> | CRC32 XFER | x32 + x7 + x5 + x3 + x2 + x + 1 |
| <crc-32-C> | CRC-32C (Castagnoli) | x32 + x28 + x27 + x26 + x25 + x23 + x22 + x20 + x19 + x18 + x14 + x13 + x11 + x10 + x9 + x8 + x6 + 1 |
| <crc-32-D> | CRC-32D | x32 + x31 + x29 + x27 + x21 + x20 + x17 + x16 + x15 + x12 + x11 + x5 + x3 + x + 1 |
| <crc-32-K> | CRC-32K (Koopman) | x32 + x30 + x29 + x28 + x26 + x20 + x19 + x17 + x16 + x15 + x11 + x10 + x7 + x6 + x4 + x2 + x + 1 |
| <crc-32-Q> | CRC-32Q | x32 + x31 + x24 + x22 + x16 + x14 + x8 + x7 + x5 + x3 + x + 1 |
| Token | Name | Polynom |
| <crc-40-gsm> | CRC-40 GSM | 0004820009 |
| Token | Name | Polynom |
| <crc-64> | CRC-64 | 42F0E1EBA9EA3693 |
| <crc-64-we> | CRC-64 WE | 42F0E1EBA9EA3693 |
| <crc-64-1b> | CRC-64 1B | 000000000000001B |
| <crc-64-jones> | CRC-64 Jones | AD93D23594C935A9 |
| Token | Description |
| <csum8-2cmp> | The checksum result added to the sum modulo 256 of all bytes in the checksum data section will equal zero. |
| <csum8-1cmp> | Same as above but sum will equal FF. |
| <csum8-sum> | The checksum result is the sum modulo 256 of all bytes in the checksum data section. |
| <csum8-xor> | The checksum result is the exclusive or of all bytes in the checksum data section. |
| <chk-8-fletcher> | Fletcher (not a CRC but a form of checksum) |
| <chk-16-fletcher> | Fletcher (not a CRC but a form of checksum) |
The checksum result occupy 1 byte for csum8-* and is placed after the data section or elsewhere if specified. A checksum can't be used with the CRC feature above, and vice-versa.
| Token | Function |
| <read> or <r> | Read message |
| <write> or <w> | Write message |
For a Read message, a token <read> or <r> must be placed before characters to besent. When clicking 'Send', the address byte is transmitted with the 'read' flag; after that, the bytes on the send line are transmitted.
For a Write message, a token <write> or <w> must be placed before characters to be sent. When clicking 'Send', the address byte is transmitted with the 'write' flag; after that, the bytes on the send line are transmitted.
By default, protocoltool assumes a write operation.