Sbep Serial Interface; General Purpose Input/Output - Motorola CDM Series Detailed Service Manual

Controller Circuits
1.10

SBEP Serial Interface

The SBEP serial interface allows the radio to communicate with the Customer Programming
Software (CPS), or the Universal Tuner via the Radio Interface Box (RIB) or the cable with internal
RIB. This interface connects to the microphone connector via control head connector (J0401-8) and
to the accessory connector J0501-17 and comprises BUS+. The line is bi-directional, meaning that
either the radio or the RIB can drive the line. The µP sends serial data via pin 98 and D0101 and it
reads serial data via pin 97. Whenever the µP detects activity on the BUS+ line, it starts
communication.
In addition, the SBEP serial interface is used to communicate with a connected control head. When
a control head key is pressed or the volume knob is rotated, the line ON OFF CONTROL goes high.
This turns on transistor Q0110 which pulls line ON OFF SENSE and µP pin 6 to ground level. In
addition, an interrupt is generated at µP pin 96. This indicates that the control head wants to start
SBEP communication. The µP then requests the data from the control head. The control head starts
sending and after all data has been sent, the ON OFF CONTROL line goes low. The control head
ignores any data on BUS+ during SBEP communication with the CPS or Universal Tuner.
1.11

General Purpose Input/Output

The controller provides eight general purpose lines (DIG1 through DIG8) available on the accessory
connector J0501 to interface to external options. Lines DIG IN 1, 3, 5, 6 are inputs, DIG OUT 2 is an
output and DIG IN OUT 4, 7, 8 are bi-directional. The software and the hardware configuration of the
radio model define the function of each port.
DIG IN 1 can be used as external PTT input, DATA PTT input or others, set by the CPS.
•
The µP reads this port via pin 77 and Q0171.
DIG OUT 2 can be used as normal output or external alarm output, set by the CPS. Transistor
•
Q0173 is controlled by the µP via ASFIC CMP pin 14.
DIG IN 3 is read by µP pin 61 via resistor R0176
•
DIG IN 5 can be used as normal input or emergency input, set by the CPS. The µP reads this
•
port via R0179 and µP pin 60. Diode D0179 limits the voltage to protect the µP input.
DIG IN 6 can be used as normal input, set by the CPS. The µP reads this port via pin 74 and
•
Q0181.
DIG IN OUT 4,7,8 are bi-directional and use the same circuit configuration. Each port uses an
•
output transistor Q0177, Q0183, Q0185 controlled by µP pins 46, 47, 53. The ports are read
by µP pins 75, 54, 76. To use one of the ports as input the µP must turn off the corresponding
output transistor.
In addition the signals from DIG IN 1, DIG IN OUT 4 are fed to the option board connector J0551
and the expansion board connector J0451.
Section 3: 1-7
Section : 6881091C63-F