3.5 TX control bits [11]
The TX control bits setting is a 8 bit value that can currently have the values:
0x00 = not valid
0x01 = CW operation
0x02 = all other operation (e.g. SSB)
---->>>>>0x04 = use the HiQSDR extended IO pins (from FPGA version 1.1 on) <<<<<--------
0x08 = simulate key down signal (software PTT)
CW operation means the TX sine signal is gener