Sbep Serial Interface; General Purpose Input/Output - Motorola 6864115B62-C Detailed Service Manual

1-6
send serial from a µP to a device, and SPI RECEIVE DATA is used to send data from a device to a
µP.
On the controller there are two ICs on the SPI BUS, ASFIC CMP (U0221-22), and EEPROM (U0111-
5). In the RF sections there are 2 ICs on the SPI BUS, the FRAC-N Synthesizer, and the Power
Control IC (PCIC). The SPI TRANSMIT DATA and CLK lines going to the RF section are filtered by
L0481 / R0481 and L0482 / R0482 to minimize noise. The chip select line CSX from U0101 pin 2 is
shared by the ASFIC CMP, FRAC-N Synthesizer and PCIC. Each of these IC's check the SPI data
and when the sent address information matches the IC's address, the following data is processed.
The chip select lines for the EEPROM (EE CS), Voice Storage (VS CS), expansion board (EXP1 CS,
EXP2 CS) and option board (OPT CS) are decoded by the address decoder U0141.
When the µP needs to program any of these IC's it brings the chip select line CSX to a logic 0 and
then sends the proper data and clock signals. The amount of data sent to the various IC's are
different, for example the ASFIC CMP can receive up to 19 bytes (152 bits) while the PCIC can
receive up to 6 bytes (48 bits). After the data has been sent the chip select line is returned to logic 1.
The Option board interfaces are different in that the µP can also read data back from devices
connected.The timing and operation of this interface is specific to the option connected, but
generally follows the pattern:
1. an option board device generates a service request via J0551-29, line RDY and µP pin 79,
2. the main board asserts a chip select for that option board device via U0141-14, line OPT CS,
J0551-30,
3. the main board µP generates the CLK (J0551-3),
4. the main board µP writes serial data via J0551-15 and reads serial data via J0551-16 and,
5. when data transfer is complete the main board terminates the chip select and CLK activity.
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). This interface connects to
the microphone connector via controlheadcontrolhead 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 microprocessor sends serial data via pin 98 and D0101 and it reads
serial data via pin 97. Whenever the microprocessor detects activity on the BUS+ line, it starts
communication.
In addition, the SBEP serial interface is used to communicate with a connected controlhead. When a
controlhead 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 controlhead wants to start
SBEP communication. The microprocessor then requests the data from the controlhead. The
controlhead starts sending and after all data has been send, the ON OFF CONTROL line goes low.
The controlheadcontrolhead 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 bidirectional. The software and the hardware configuration of the
radio model define the function of each port.
THEORY OF OPERATION