Initiating a Register Read

Like standard SCD communication, INIT should be set, INSTRWA should be polled and AGS should be set.

Before this instruction is set, CDMTO should be polled. This status bit allows the user to poll CDMTO to confirm that the required 14 CDM low bits have been transmitted. Once this is set up, an instruction value can be written into the INSTR register to instruct the BiSS engine the type of instruction/command that will be executed. INSTR should not be written to while it is in progress of fulfilling an instruction, therefore INSTRWA should be polled again.