Ok, it may be just peanuts, but here
the author says that the max. length (i.e. max. bit stuffing) of the flexible data rate part of a 64 Byte payload frame is 673 bit (Figure 6).
That part consists of:
- ESI (1 bit)
- DLC (4)
- Data field (64 * 8 + x stuff)
- CRC (21 + 6 stuff )
- CRC Delimiter (1)
Now, 673 is the sum of the above plus 128 stuff bits. However that means that he considered a stuff bit after four consecutive bits of the same level, like it is done for the CRC part.
But in the Data Field a stuff bit has to be inserted after five consecutive bits, hasn't it?
Therefore, the max. length of the Data field is 512 + 512/5 = 615 bit, what gives a maximum of 648 instead of 673 bit.
Am I correct?