PRC1099A-MS
9-1
Chapter 9: Processor Board
9.1
Circuit Description
The Processor board includes a processor and associated components to
perform the following control functions in the transceiver:
• Tuning of the synthesizer
• Harmonic filter selection
• Antenna tuner control
• Driving of the LCD frequency display
• Applying the signals from the front panel switches, knobs, and buttons
Communication with the external boards is conducted through a SPI (serial
peripheral interface) data bus. The processor operates only during the period
required to perform its specific control functions. This gives two important
operational advantages. The first is that the processor only draws current during
the brief period required to perform the control functions, typically only a few
milliseconds. The second advantage is that there is no need to provide extensive
shielding to stop noise in the receiver. The processor operates only when
controls are changed.
The Processor board also has interface capabilities to an optional ALE card.
The Processor board contains a Motorola 68302 processor that performs all
radio control functions. The following sections discuss the components of the
block diagram on the following page.