Figure 3-7. Vocon Board - Controller Section - Motorola ASTRO Digital Spectra Plus Service Manual

3-16
The SLIC (U206) performs many functions as a companion IC for the MCU. Among these are
expanded input/output (I/O), memory decoding and management, and interrupt control. It also
contains the universal asynchronous receiver transmitter (UART) used for the RS232 data
communications. The SLIC control registers are mapped into the MCU (U204) memory space.
U201
32Kx8
EEPROM
U202
32Kx8
SRAM
U205
256Kx8
FLASH
U210
256Kx8
FLASH
HC11/DSP
Interface
The controller performs the programming of all peripheral ICs. This is done via a serial peripheral
interface (SPI) bus. ICs programmed through this bus include the synthesizer prescaler, DAIC, and
ADSIC. On secure-equipped model, the encryption board is also controlled through the SPI bus.
In addition to the SPI bus, the controller also maintains two asynchronous serial buses; the SB9600
bus and an RS232 serial bus. The SB9600 bus is for interfacing the controller section to different
hardware option boards, some of which may be external to the radio. The RS232 is used as common
data interface for external devices.
User input from the control head is sent to the controller via the SB9600 bus. Feedback to the user is
provided by the display on the control head. The display is 2 line 14 characters on the W3 model, 8
characters on W4, W5, and W7 models, and 11 characters on the W9 model.
The controller schedules the activities of the DSP through the host port interface. This includes
setting the operational modes and parameters of the DSP. The controlling of the DSP is analogous to
programming analog signaling ICs on standard analog radios.
October 28, 2002
1024 Bytes
SRAM
Address/Data/
Control
U204
MC68HC11F1
Resets
SLIC IV
Address/Data/
Control
Chip Selects/
Bank Control

Figure 3-7. VOCON Board - Controller Section

Theory of Operation: ASTRO Spectra VOCON Board
SCI
512 Bytes
EEPROM
SPI
General
Purpose I/O
Clocks A/D
Clocks
U206
Controls
General
Purpose I/O
RS232
Command Board
Command Board
ADSIC
Encryption Board
Command Board
MAEPF-25105-O
6881076C25-D