User Manual

SECTION 1: THEORY OF OPERATION
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System Controller Block Diagram
Functional block diagram of the System Controller.
The system controller controls all programmable devices in the radio and handles internal and external
communications.
Microcontroller Description
The base station uses a SGS/Thomson ST10F167 microcontroller. It is a highly integrated processor
with many on chip peripherals including:
• 128K bytes of on chip Flash EPROM for program storage
• 4K bytes RAM
• UART (asynchronous serial interface)
• Synchronous serial interface
• Analog-to-digital converter
• General purpose timers
• Watchdog timer
• Reset generator
• Programmable chip selects
• Clock multiplier
• General purpose I/O pins
In addition to the microcontroller on chip memory, there are also 512K bytes of RAM for data buffers and
system use, and 2K bytes of non-volatile memory for configuration information.
Message Processing
For down-link data transmissions, the microcontroller receives data from the serial port, determines the
start and end of data frames, formats the data for transmission, turns on the transmitter, and passes the
data to the transmit modem chip. At the end of the transmission, if no other messages are ready, the
microcontroller turns off the transmitter.