Motorola ASTRO Digital Saber, Руководство по обслуживанию

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7
-
8
The ADSIC contains four general purpose I/O labeled GCB0 -GCB3.
These are connected to the AUDIO PA and are used for enabling the
speaker and microphone amplifiers in the IC and for steering the
speaker and microphone audio paths from internal to external. These
I/O are controlled by the DSP through the ADSIC parallel
configuration bus. The DSP then writes speaker data samples to the
speaker D/A register through the parallel bus at an 8kHz rate and
configures the AUDIO PA enable lines by writing the same bus to the
register controlling the I/O.
The audio PA provides about 20dB of gain and a dual ended
differential output; SPKR_COMMON, and EXT_SPKR or INT_SPKR.
Internal or external speaker drive is achieved by changing the phase of
the outputs on INT_SPKR and EXT_SPKR to be either in phase or out
of phase with SPKR_COMMON. The signal which is out of phase with
SPKR_COMMON will be driven.
Since all of the audio and signaling is processed in DSP software
algorithms, all types of audio and signaling follow this same path.
TX Signal Path
The transmit signal path follows some of the same design structure as
the receive signal path described above in section D (refer to Figure 7).
It is advisable to read through the section on RX Signal Path prior to
this section.
The ADSIC contains a microphone A/D with a programmable
attenuator for coarse level adjustment. As with the speaker D/A
attenuator, the microphone attenuator value is programmed by the
MCU through the SPI bus. The analog microphone signal from the
Audio PA (U401) is input to the A/D on MAI (Mic Audio In). The
microphone A/D converts the analog signal to a series of data words
and stores them in internal registers. The DSP accesses this data
through the parallel data bus parallel configuration bus consisting of
D8-D23, A0-A2, A13-A15, RD*, and WR*. As with the speaker data
Figure 7 . DSP RSSI Port - TX Mode
48KHz TX Data Interrupt
Serial Transmit Data
Serial Receive Data
2.4 MHz Receive Data Clock
20 KHz RX Data Interrupt
1.2 MHz Tx Data Serial Clock
D8-D23
A0-A2,A13-A15,RD*,WR*
SCKR
RFS
TFS
SCKT
RXD
TXD
ADSIC
U406
GCB0-GCB3
To
Audio PA
U401
MAI
VVO
MODIN
J401-15
SC0
SC1
SC2
SCK
SRD
STD
SSI
SERIAL
DSP56001
U405
IRQB IRQB
8KHz
SBI
DIN
DIN-
IDC
ODC
Data In
Data In*
SBI
ABACUS II
Interface
J401-1
J401-2
J401-8
J401-4
MAEPF-24340-O