6871620L01-C
May 28, 2008
Theory of Operation:
Transceiver Section
3-3
3.1.1.2 Transceiver and VOCON Section Interface
The transceiver and VOCON section interface is a digital interface carrying DC power, control, and
data between the XCVR and VOCON sections.
lists the interface connections, their signals, and functions. SPI refers to serial peripheral
interface, which is the control bus from the microprocessor. SSI is the serial synchronous interface
bus for data to and from the DSP. There is a RX SSI bus for demodulated data from the receiver and
a TX SSI bus for modulation data to the transmitter.
3.1.1.3 Antenna Contact M1704
Antenna contact M1704 is a surface mount, leaf spring contact which comes into contact with the
antenna pin on the radio chassis assembly. This contact routes the RF power to/from the transceiver
to the antenna.
Table 3-2. Transceiver – VOCON Interface Signals
VOCON Signal
XCVR
Signal
XCVR
I/O
Type
Description
X1
FUB+
O
dc
Fused B+ to VOCON
XLOCK
LOCK
O
status
FGU lock detect
XTX_DATA
TXTD
O
ssi
TX SSI data
XSSI_CLK
RXCK
O
ssi
RX SSI clock
XSSI_FSYNC
RXFS
O
ssi
RX SSI frame sync
X16.8MHz
F168
O
RF
16.8 MHz reference clock
XSWB+2
X
I
dc
Switch control
XTX_SSFS
TXFS
I
ssi
TX SSI frame sync
XTS_SSCK
TXCK
I
ssi
TX SSI clock
XRX_DATA
RXDO
O
ssi
RX SSI data
XABACUS3_CS
ABCS
I
ssi
SPI Abacus chip select
XRF_VSW1
VSW1
I
dc
Regulated 3.8 V
XRF_SCKA
SPCK
I
spi
SPI clock
XRF_BAT_STAT
DATA
O
dc
Battery status
XRF_MOSIA
MOSI
I/O
spi
SPI data I/O
XFN_PC_SEL
USEL
I
spi
SPI universal chip select
XRF_POR
RSTL
I/O
control
asynchronous reset, active low
Summary of Contents for ASTRO XTSTM 4000
Page 1: ...COLOR CHORDS 7 ASTRO XTSTM 4000 Portable Radio Detailed Service Manual ...
Page 2: ......
Page 16: ...May 28 2008 6871620L01 C xiv Commercial Warranty Notes ...
Page 22: ...May 28 2008 6871620L01 C 1 6 Introduction Notes ...
Page 26: ...May 28 2008 6871620L01 C 2 4 Radio Power Notes ...
Page 56: ...May 28 2008 6871620L01 C 3 30 Theory of Operation Notes ...
Page 100: ...May 28 2008 6871620L01 C 6 8 Troubleshooting Waveforms Notes ...
Page 194: ...May 28 2008 6871620L01 C B 2 Motorola Service Centers Notes ...
Page 204: ...May 28 2008 6871620L01 C Glossary 10 Glossary Notes ...
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