IIR
iv. Read PCH FDI Receiver ISR ([DevIBX-B+] IIR) for bit lock in bit 8 (retry at least once if no lock)
vii. Read PCH FDI Receiver ISR ([DevIBX-B+] IIR) for symbol lock in bit 9 (retry at least once if no
fCachedIIR = ReadReg8(IIR);
iir = ReadReg8(IIR);