Datron PRC1099A - Page 151

9: Processor Board
9-2 PRC1099A-MS
9.1.1 Processor
Processor U1 is combined with the input/output circuits to form a special
purpose microcomputer. It controls the operation of the transceiver in
response to the control inputs, in accordance with the program stored in
memory.
The processor is a Motorola MC68302 that uses a 68000 processor core. This
processor has the capability of addressing up to 2 Mb of EPROM memory and
64 kB of static RAM for future program expansion. It also has three UARTS,
two timers, 18 bidirectional input/output lines, and four external interrupt
sources.
The processor operates at a clock frequency of 4 MHz and uses an internal
oscillator controlled by Y1. UART1 provides RS-232 communications
through the front panel Accessory connector. UART2 communicates with the
optional ALE card.
PA2 through PA7 drive the control bus, while PA10 through PA14 are for the
d-mux bus. PA15 and PB0 through PB4 are for miscellaneous control
functions.
Figure 9-1 Processor Board Block Diagram
Analog
Inputs
RS-232
COMMS
Control
Bus
Processor
Control
Inputs
Control
Inputs
GP12
ALE TX
Audio
ALE RX
Audio
TA TX
Audio
TA TX
Audio
Microprocessor
Clock
Oscillator
RS-232
I/O
Control
Bus
Outputs
Control
Outputs
Input
Demultiplexer
Microprocessor
Controller
Memory
Backup
EPROM
Memory
Storage
RAM
Memory
Storage
Analog
Converter
System
ALE
Switch
EPROM
Audio Buffers
TX
Audio
RX
Audio
Interrupt
Signaller
State
Change
Detector
Wake up Control