MX800 Transceiver Technical Manual
© SPECTRA ENGINEERING 2006 Revision 4.2.3
70
4.4.1 Overall Radio Management
In addition to analogue signal processing circuitry the Micro Controller board
accommodates an 80C552 microprocessor IC1, a 64kbyte EPROM IC3,
32kbyte RAM IC4, a 16kbyte EEPROM as well as address decoding, I/O
latches and other miscellaneous circuitry. The Micro Controller is responsible
for ensuring that the radio acts as programmed by the user. It stores the user-
entered parameters for each channel in EEPROM. This information includes
RX and TX RF frequencies; RX and TX CTCSS frequencies as well as RF
output power and operating mode. An 8-channel analogue to digital converter
allows the microprocessor to read 8 analogue values internal to the radio,
which in conjunction with the digital inputs to the microprocessor allow the
operating status of the radio to be monitored and controlled.
The following analogue items are read:
Port
Parameter
ADC0 Received Signal Strength Indication (RSSI)
ADC1 Detected Discriminator output level
ADC2 DC operating voltage
ADC3 RX VCO tuning Voltage
ADC4 TX VCO tuning Voltage
ADC5 PA temperature
ADC6 PA forward power
ADC7 PA reflected power
Table 4-1 Microprocessor Port Parameters
The Micro Controller sends programming data to the synthesiser ICs on the
Receiver and Exciter modules each time the channel is changed as well as on
PTT. This information is communicated to the Receiver and Exciter modules
by way of bussed data and clock lines on SKC/D-18 and SKC/D-15
(Exciter/Receiver) and an individual module strobe on SKC/D-17. A lock
detect signal from each module on SKC/D-16 is read by the micro controller.
In addition to the synthesiser programming bus an I
2
C bus goes to each of the
modules. This bus is currently unused.
IC25 is a non-predictive, full duplex CTCSS encoder/decoder, which is under
the control of the microprocessor.
To Next Page
Loading...