Motorola DSP56012 Manual Do Utilizador
8-6
DSP56012 User’s Manual
MOTOROLA
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.
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
registers are described in the following subsections. The Interrupt Vector table for the
DAX is shown in
DAX is shown in
8.5
DAX INTERNAL ARCHITECTURE
Hardware components shown in
following sub-sections. The DAX programming model is illustrated in
Table 8-1
DAX Interrupt Vectors
Condition
Address
Description
XADE & XAUR
P:$0050
DAX Transmit Underrun Error
XADE & XBLK
P:$0052
DAX Block Transferred
XADE
P:$0056
DAX Transmit Register Empty
Table 8-2
DAX Interrupt Priority
Priority
Interrupt
highest
DAX Transmit Underrun Error
DAX Block Transferred
lowest
DAX Transmit Register Empty