Controller - Motorola PRO1150 Manual De Uso

PRO1150™ Service Manual

Controller

Voice Synthesis
A TSP50C10 is used to provide voice playback to the
user for selection of channel PL code and language
(English, Spanish, French, or Portuguese). Please
refer to the Owner's Manual for operation, where
applicable.
Logic
The MC68HC11 microcontroller is being used to
perform all software functions for the radio. All
tuning functions are automatic, and accessed via
the SCI bus on the microcontroller. External test
pads are available to connect to the SCI bus.
An internal EEPROM (256x8) stores all auto-tuning
information. This includes warping the 16.8 MHz
TCXO, squelch, transmit audio deviation, transmit
TPL deviation, and output RF power. All PL
decoding functions are performed in software.
Radio functions, such as Push-To-Talk (PTT) and
monitor, are processed and interpreted by the
microcontroller. Sensing circuitry on the
microphone input allows the microcontroller to
accommodate external PTT. All clock frequencies
are derived from the 16.8 MHz TCXO, which is
divided-down internally by the ULTZIF.
DC Power Supply (2.75V and 5.0 V)
The radio's main regulated power supply consists of
a National Semiconductor® LP2951C voltage
regulator, strapped for 2.5 V. The regulator also has
a RESET pin function which ensures an orderly
power-up sequence for the microcontroller and
other ICs. A second voltage regulator is also
included in the design; it provides 5.0 volts for the
compandor IC, voice IC, and the steering line for
the VCO. A 7.5 V nickel-cadmium (NiCd) battery
pack (consisting of 6 cells, 2/3 AF) serves as the main
power source for the regulators and transmit
circuitry. Bipolar transistors are used to switch
supply voltages to the appropriate circuits when
operating in either transmit, receive, or standby
mode.
English
Theory of Operation
Controller
4-3