Audio Interface Module (AIM)MCF5253 Reference Manual, Rev. 117-16 Freescale Semiconductor17.6.1 IEC958 Receive InterfaceThe IEC958 (SPDIF) receive interface consists of 2 blocks:1. The source selector2. The IEC958 receiver itselfThe source is selected by programming the appropriate EBU Control Register bits 7:6. The receiver thenextracts the data from the stream and outputs the data on the internal audio bus. The data can then be usedby the processor (using the PDIR and other registers) or by the IIS or EBU transmit interface. In the caseof the data being used as input to one of the IIS transmitters, the data rate of the incoming EBU data mustmatch exactly with that of the IIS transmitter. The following functions are performed by the block.17.6.1.1 Audio Data ReceptionThe IEC958 receive block (19) extracts the audio data from the stream and puts this in 20-bit format onthe Internal Audio Data bus. The format is exactly the same as the format produced by the serial datainterfaces.17.6.1.2 Control Channel Reception Register DescriptionsThere are two 32-bit registers, one for each receiver, which receive the first 32 bits of the “C” channel. Nointerpretation is done. For a description of the control (or “C”) channel in EBU data formatting, refer tothe IEC958-3 specification’s description of control channel. Figure 17-9 illustrates the valid bits in theEBURcvCChannel.Table 17-7. EBU2Config Register Field DescriptionsField Description Reset7–6 IEC958 Receive source select.00 EBU in 101 EBU in 210 EBU in 311 EBU in 400
