Astro Spectra Plus Vocon Board; General; Astro Spectra Plus Controller Section - Motorola ASTRO Digital Spectra Plus Detailed Service Manual

3-38
3.4

ASTRO Spectra Plus VOCON Board

This section of the theory of operation provides a detailed circuit description of an ASTRO Digital
Spectra Plus Vocoder/Controller (VOCON) board. When reading the Theory of Operation, refer to
your appropriate schematic and component location diagrams located in
Component Location Diagrams and Parts Lists"
help isolate the problem to a particular component. However, first use the ASTRO Digital Spectra
and Digital Spectra Plus Mobile Radios Basic Service Manual to troubleshoot the problem to a
particular board.
NOTE: The information in this subsection applies to the Plus VOCON board. Refer to Section
3.3, "ASTRO Spectra VOCON Board," on page 3-15
VOCON (non Plus) board.
3.4.1

General

The ASTRO Spectra Plus VOCON board consists of two subsystems; the vocoder and the
controller. Although these two subsystems share the same printed circuit board and work closely
together, it helps to keep their individual functionality separate in describing the operation of the
radio. The controller section is the central interface between the various subsystems of the radio. It is
very similar to the digital logic portion of the controllers on many existing Motorola radios. Its main
task is to interpret user input, provide user feedback, and schedule events in the radio operation,
which includes programming ICs (Integrated Circuits), steering the activities of the DSP (Digital
Signal Processor), and sending messages to the display through the control head. The vocoder
section performs functions previously performed by analog circuitry. This includes all tone signaling,
trunking signaling, and conventional analog voice, etc. All analog signal processing is done digitally
utilizing a DSP56600. In addition it provides a digital voice plus data capability utilizing IMBE voice
compression algorithms. Vocoder is a general term used to refer to these DSP based systems and is
short for voice encoder. In addition, the ASTRO Spectra Plus VOCON board provides the
interconnection between the MCU (microcontroller unit), DSP, command board, and UCM (Universal
Encryption Module) on secure-equipped radios.
3.4.2

ASTRO Spectra Plus Controller Section

Refer to Figure 3-14 on page 3-39
The controller section of the ASTRO Spectra Plus VOCON board consists entirely of digital logic
comprised of a microcontroller unit core (Patriot IC-U300), and memory consisting of: SRAM (U302),
and FLASH ROM (U301). The Patriot IC is a dual-core processor that contains a DSP56600 core, a
MCore 210 microcontroller core and custom peripherals. Note: When the Controller Section
references the MCU, it will be referencing the Mcore 210 inside the Patriot IC (U300).
The MCU (U300) memory system is comprised of a 256k x 16 SRAM (U302) and a 2M x 16 FLASH
ROM (U301). The MCU also contains 22.5k x 32 of internal SRAM. The FLASH ROM contains the
programs that the Patriot IC executes, and is used to store customer specific information and radio
personality features (i.e. codeplug information). The FLASH ROM allows the controller firmware to
be reprogrammed for future software upgrades or feature enhancements. The SRAM is used for
scratchpad memory during program execution.
The controller performs the programming of all peripheral ICs. This is done via a serial peripheral
interface (SPI) bus, and through General Purpose Input/Outputs (GPIO) from the Patriot IC. ICs
programmed through these interfaces include the Synthesizer, Prescaler, DAIC, and KRSIC (U200)
and ADDAG (U201).
September 5, 2008
Theory of Operation: ASTRO Spectra Plus VOCON Board
of this manual. This detailed Theory of Operation will
and your specific schematic diagram located in Chapter 7.
"Chapter 7. Schematics,
for information on the ASTRO Spectra
6881076C25-E