4.9 MASTER INTERFACE SIGNALS

• IMAS - Master.
  IMAS high indicates that the device is the current Master. If you are building a `Slave only' device, tie this pin low.

  More specifically, IMAS high will set up a transmit data path from BD to the AD lines if RD is low, or pass AD signals to BD if RD is high. It also enables IMEL. Using IMAS it is possible to achieve a degree of pipelining in block transfer operations using the data latch in the ADIs; the parity generator in the ADIs may also be used. See Section 11.12 for an application note.

• IMEL - Master Enable Latch.
  When IMAS is true, IMEL generates OEL to the ADIs and enables a latch for detected parity error. The latched parity error generates OMPE, Master Parity Error.

• OMPE - Master Parity Error.
  This is for Master applications. If the PCL is used in the Slave part of a Master, then the PCL/ADI set will carry out parity checking on data read operations performed by the Master, and indicate the result on OMPE. (Parity generation for the Segment signal during Master Write operations is performed automatically.) See Section 11.12 for applications.