Use if TCK/SK starts at '0'.
This will clock out bits on TDI/DO from 1 to 8 depending on the Length byte. A length of 0x00 will do 1 bit and a length of 0x07 will do 8 bits. The data is sent LSB first. Bit 0 of the data byte is placed on TDI/DO then the TCK/SK pin is clocked. The data will change to the next bit on the falling edge of the TCK/SK pin.