0x24,
LengthL,
LengthH
This will clock in bytes on TDO/DI from 1 to 65536 depending on the Length bytes. A length of 0x0000 will do 1 byte and a length of 0xFFFF will do 65536 bytes. The first bit clocked in will be the MSB of the first byte and so on. The data will be sampled on the falling edge of the TCK/SK pin.