SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
The XMODEM protocol is used to transfer boot data. Only CRC mode is supported (not checksum), with both 128- and 1024-byte block sizes. The general, format of received frames is shown in Table 4-74 and Table 4-75.
STX | Block Num | Inv Block Num | 1024 data bytes | CRC | CRC | |||
SOH | Block Num | Inv Block Num | 128 data bytes | CRC | CRC |
Field | Value | Description |
---|---|---|
STX | 0x02 | The start character for 1024-byte CRC data blocks |
SOH | 0x01 | The start character for 128-byte CRC data block |
Block Num | 0x01-0xFF – 0x00 | The block number. The first block has value 1, and the block number wraps around 0xFF to 0 |
Inv Block Num | 0xFE-0x00 | The inverse block number (bit inverse of the block number) |
CRC | Calculated | The 16-bit CRC generated from the polynomial 0x1021 |
The XMODEM protocol is implemented as a half-duplex protocol as shown in Table 4-76.
Transmitter Sends | Receiver Sends | |
---|---|---|
← | Ping (‘C’) | |
Frame 1 | → | |
← | ACK (or NACK) | |
Frame 2 | → | |
← | ACK (or NACK) | |
EOT | → | |
← | ACK (or NACK) |