Motorola MTR2000 Service Manual page 102
Base station, repeater and receiver
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Also See for MTR2000:
- Manual (176 pages) ,
- Installation and operation manual (79 pages) ,
- Instruction / field service manual (43 pages)
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STATION CONTROL MODULES
MODEL TCN6273C
68P81094E31-B
Schematics (Sheet 8 of 36)
01/05/97
SERVICE NOfES•HOST CORE
Signal
Description/Nominal Signal Levels
Path
®
VCC pin connected to the Battery Backup pin of U4007, to preserve the RAM content in case of power
failure.
®
Host Data Bus is split in 2 by the U4005 buffer: Host_Master_Data
bus connects the memory devices and Host_Data bus connects the rest of the IC's (I/O's) on this data
bus.
©
While in Read mode, R4050 is not placed and the RP
~in
on the flash IC (U4003) is tied to the Reset
pin on the processor via 04002, anii the boot block is ocked. When the Boot Block needs to be
programmed (Write mode), R4050 is soldered in and the RP pin is tied to 12V via 04003 and R4050.
SCHEMATIC IC'S TABLE• HOST CORE
Reference
Type
Description
U4000
MC68356
Signal Processing Communication Engine
U4001,2
HM628128
CMOS Static RAM, 128 • 8 byte
U4003
TB28F400
256•16 Boot Block Flash Memory
U4004
MC74AC138
1 of 8 Decoder /Demultiplexer
U4005
MC74AC245
Octal Bidirectional Transceiver With 3-State 1/0
U4006 ...
MC74AC08
Quad 2 input AND Gate
U4007
MAX703
uP Supervisory Circuit with Battery Backup
U4201...
MC74AC32
Quad 2-input OR gate
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