Sailor RE2100, Technical Manual

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5 CIRCUIT DESCRIPTION AND SCHEMATIC DIAGRAMS RE2100
5.5 PROCESSOR UNIT (MODULE 5) PART NO. 625635
The processor module has been built up around a microprocessor of the type HD63B03VP with belonging
8.005 MHz crystal. The purpose of the microprocessor is to control the other modules in the RE2100 by
means of a Serial Peripheral Interface Bus (SPI), and to scan the keyboard. Furthermore the processor
must also control the Serial Communication Interface Bus (SCI), also called the SP-BUS.
MICROPROCESSOR
The microprocessor module is normally equipped with a ROM less processor, type HD63BO3VP,
however mass produced types may also occur. The placing of a strap in P02 informs the processor from
where to read the programme. If the strap is placed between pin 1 and pin 2, the programme is read from
the internal ROM store. If the strap is placed between pin 2 and pin 3, the programme is read from the
external store (27C128/27C256). The internal clock frequency of the processor is 2 MHz.
WATCH DOG
The microprocessor supervising circuit U15 works as watch dog and power sense.
In U15, pin 6 (watch dog input) the level must change at least once every 1.6 sec. If not, the U15 generates
a reset pulse to the microprocessor.
Power fail input U15, pin 4 detects when the 9V supply falls below 7.0V. In this case, the microprocessor
receives an interruption via power fail output U15, pin 5. The programme starts storing data in the
EEPROM. This function is used when the receiver is switched off (see the paragraph below: ON BOARD
POWER SUPPLY).
When VCC to U15 is below 4.65V the reset output U15, pin 7 goes low, and the U15 does not generate
a reset to the microprocessor until the VCC is above 4.75V again.
MEMORY
The microprocessor has two memory circuits. One for programmes and one for data.
The programme memory U06 is a 16 or 32 kbyte PROM, e.g. the type 27C128/27C256 with a max. access
time of 250 nS. If 16 kbyte is used, the strap in PO1 is mounted between pin 2 and pin 3. When 32 kbyte
is used, the strap is mounted between pin 1 and pin 2.
The data memory U05 is an 8 kbyte EEPROM, e.g. the type 28C64 with max. access time of 250 nS.
Furthermore it must contain page mode programming of min. 16 kbyte. U15 contains data, such as
frequency tables, country versions, scanning tables, and latest set-up after the receiver has been
switched off.
KEYBOARD
The keyboard module 6 has been built-up as a 4x8 matrix of which 26 keys are used. The keyboard is
scanned by means of 4 ports from the microprocessor and the data bus. When the processor reads from
the keyboard, access is made to the bus driver U04.
EXT. PORT
The Bus Driver U19 acts as an 8-bit input port, which is connected to the internal Data Bus.
ON BOARD POWER SUPPLY
On this PCB, 3 power supplies are found, i.e. 5VA, 5VB and -5VB.
5VA (U16) supplies the microprocessor, memory, watch dog, baud rate generator, and address select.
5VB (U17) supplies the remaining circuits, using +5V.
-5VB (U18) supplies half of the SP-Bus transmitter.
Power supply 5VA is a low drop 5V regulator. The power supply also works as a power back-up, when
the 9V supply disappears. C11 is able to keep the supply for the microprocessor for approx. 50 mS after
the 9V supply has disappeared.
The microprocessor spends approx. 20 mS for storing the data in U05. A parallel connection of C14 and
C45 has been carried out in order to keep the serial resistance below 1 ohm at low temperatures.
Power supply 5VB is a standard 5V regulator (LM340T5).
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