Dax Programming Model; Dax Internal Architecture; Table 8-1 Dax Interrupt Vectors; Table 8-2 Dax Interrupt Priority - Motorola DSP56012 User Manual

Digital Audio Transmitter

DAX Programming Model

The second sub-frame transmission (Channel B) starts with the preamble generator
generating the Channel B preamble (Y-preamble). At the same time, Channel B audio
and non-audio data is transferred to the XADSR shift-register from the XADBUF and
XNADBUF registers. The generated Y-preamble is output immediately after the
Channel A parity and is followed by the audio and non-audio data in the XADSR,
which is in turn followed by the calculated parity for Channel B. This completes a
frame transmission. When the Channel B parity is sent, the audio data for the next
frame, stored in the XADRA/XADRB and the non-audio data bits from the XCTR,
are uploaded.
8.4

DAX PROGRAMMING MODEL

The programmer-accessible DAX registers are shown in Figure 8-2 on page 8-7. The
registers are described in the following subsections. The Interrupt Vector table for the
DAX is shown in Table 8-1. The internal interrupt priority is shown in Table 8-2.
Condition
XADE & XAUR
XADE & XBLK
XADE
Priority
highest
lowest
8.5

DAX INTERNAL ARCHITECTURE

Hardware components shown in Figure 8-1 on page 8-4 are described in the
following sub-sections. The DAX programming model is illustrated in Figure 8-2.
8-6

Table 8-1 DAX Interrupt Vectors

Address
P:$0050
P:$0052
P:$0056

Table 8-2 DAX Interrupt Priority

DAX Transmit Underrun Error
DAX Block Transferred
DAX Transmit Register Empty
DSP56012 User's Manual
Description
DAX Transmit Underrun Error
DAX Block Transferred
DAX Transmit Register Empty
Interrupt
MOTOROLA