User`s guide

3-6
The GUTC board with a Motorola g20 radio is shown in Figure 3-6. An earlier g18-
based board can be converted to g20 operation using the adapter board shown in this
figure. The conversion process is discussed in an upcoming chapter. New firmware is
required when making this change.
Figure 3-6
GUTC Circuit Board with g20 Radio
A simplified block diagram of the GUTC board is illustrated in Figure 3-7. At the core of
the system is the MSP-430 microcontroller. This processor is part of a new generation of
high performance microcontrollers integrating RAM, Flash memory, serial I/O ports, and
other functions. An external EEPROM memory serves to retain data contents even in the
case of a total power loss. A configuration port is accessible via J5. The Motorola cellular
radio module mounts directly on top of the GUTC board, with the electrical connections
made using a 28-pin connector. Power for the radio is switched on/off using a power
transistor switch circuit located on the GUTC board. Lastly, a voltage regulator for the
GUTC board reduces the applied input voltage to a level that can be tolerated by the
MSP-430 processor (3.3 volts dc).