Operating Modes – Normal, Network, And On-Demand - Motorola DSP56367 User Manual

Enhanced Serial Audio Interface (ESAI)
Operating Modes
6. ESAI Transmit Last Slot Interrupt
Occurs, if enabled (TLIE=1), at the start of the last slot of the frame in network mode
regardless of the transmit mask register setting. The transmit last slot interrupt may be
used for resetting the transmit mask slot register, reconfiguring the DMA channels and
reassigning data memory pointers. Using the transmit last slot interrupt guarantees that
the previous frame was serviced with the previous setting and the new frame is
serviced with the new setting without synchronization problems. Note that the
maximum transmit last slot interrupt service time should not exceed N-1 ESAI bits
service time (where N is the number of bits in a slot).
7. ESAI Transmit Even Data
Occurs when the transmit even slot data interrupt is enabled (TEDIE=1), at least one
of the enabled transmit data registers is empty (TDE=1), the slot is an even slot
(TEDE=1), and no exception has occurred (TUE=0 or TEIE=0).
Writing to all the TX registers of the enabled transmitters or to TSR clears this
interrupt request.
8. ESAI Transmit Data
Occurs when the transmit interrupt is enabled (TIE=1), at least one of the enabled
transmit data registers is empty (TDE=1), no exception has occurred (TUE=0 or
TEIE=0), and no even slot interrupt has occurred (TEDE=0 or TEDIE=0).
Writing to all the TX registers of the enabled transmitters, or to the TSR clears this
interrupt request.
10.4.4 OPERATING MODES – NORMAL, NETWORK, AND
ON-DEMAND
The ESAI has three basic operating modes and many data/operation formats.
10.4.4.1 Normal/Network/On-Demand Mode Selection
Selecting between the normal mode and network mode is accomplished by clearing or setting
the TMOD0-TMOD1 bits in the TCR register for the transmitter section, and in the
RMOD0-RMOD1 bits in the RCR register for the receiver section.
For normal mode, the ESAI functions with one data word of I/O per frame (per enabled
transmitter or receiver). The normal mode is typically used to transfer data to/from a single
device.
For the network mode, 2 to 32 time slots per frame may be selected. During each frame, 0 to
32 data words of I/O may be received/transmitted. In either case, the transfers are periodic.
The frame sync signal indicates the first time slot in the frame. Network mode is typically
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