Motorola MTR2000 T5544 Instruction / Field Service Manual page 224

68P81096E53-C
09/30/05
Output Circuits
As shown in the block diagrams, the Auxiliary I/O Board contains SPI
Output Latches and associated circuitry which provides an output signal
path from the station SCM to auxiliary equipment.
The Latches are selected by using the OP1/2_CS2 (Chip Select).
A serial SPI data block is routed from the Controller which contains the ac-
tual 16 Bit Output Pattern and is stored in the SPI Output Latches. After
buffering by transistor stages the output information is made available for
the auxiliary equipment.
The output circuitry comprises 16 general purpose outputs of which 12 are
available; 7 of these 12 outputs are dedicated and 5 are user programmable
(see Table 5 or the RSS Online Help for details):
- GPO_0 to GPO_2 are TTL outputs; maximum 40V, 50mA sink cur-
rent. GPO_8 to GPO_13 are open collector transistor outputs; maxi-
mum 40V, 100mA sink current.
- GPO_14 and GPO_15) can be configured as dry (potential free) con-
tact outputs (relay); contact rating is 250V, 1 A maximum.
- In addition there is a RF Relay Transistor Drive Stage provided which
can be used for base station backup configurations; 40V, 100 to
200mA maximum sink current.
The Auxiliary I/O Board also provides some fast reacting outputs which
are directly controlled by the SCM processor and which bypass the SPI
Latches. This avoids the time consuming SPI write and store process. The
fast reacting output functions are Fast Carrier Detect, AC Fail, and RdStat.
They are jumper selectable and routed to the Output Transistors of
GPO_14 (see Table 7) and GPO_15 (see Table 8).
The Initialization and Reset Control Circuit of this board provides a con-
trolled startup and reset of the output registers during the powerup or re-
set process. This ensures that no erroneous data is seen by the auxiliary
equipment before the Controller defines the outputs. This circuit also
suppresses the Opt IRQs generated during reset and startup.
Table 2 provides a description of the SPI Bus input circuitry signals.
Auxiliary I/O Board
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