Sailor RE2100, Техническое руководство

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5 CIRCUIT DESCRIPTION AND SCHEMATIC DIAGRAMS RE2100
5.7 DISPLAY UNIT (MODULE 7) PART NO. 625637
The display module uses 13 pcs. 7 segments (U08-U20), 12 pcs. LED (DO3 -D14) and 1 pc. LED-bar
(U01) for reading-out information to the operator.
DISPLAY DRIVER
The display driver U03-U05 is a serial read-in driver, which is able to drive 34 segments. U03, U04, and
U05 in combination drive the RX and TX display and the individual LEDs, except from D06 and D07
(indication of Dummy Load and Tune)
The 34 bit data for each display driver is read-in serially by means of the internal SPI-Bus. The power in
the individual segments is determined by the power in Brightness input, pin 19. The Brightness control
circuit consists of Q03, Q04, Q05, and U07. The adjustment takes place in 4 steps:
1) OFF. All segments are off. U06, pin 15, 1 and 2 are high,
2) Min. The power in the segments is approx. 0.5 mA. U06, pin 15 goes low.
3) Normal. The power in the segments is approx. 1.0 mA. U06, pin 2 goes low.
4) Max. The power in the segments is approx. 3.5 mA. U06, pin 15 goes low.
DUMMY LOAD AND TUNE LED
For read-out of the dummy load and tune functions, 2 separate LED’s are used. These LEDs cannot be
reduced or switched off after the functions have been selected. The two LEDs are controlled by U06
(74HC595) an 8 bit serial register, which is also supplied by the internal serial SPI-Bus.
KEYBOARD LIGHT DRIVER
When the light in the keyboard is turned on, U06, pin 3 goes low, after which Q02 is turned on and supplies
the 13 pcs. LEDs on the keyboard with 8V. The zener diode D15 (5V1) prevents Q02 from turning on when
U06, pin 3 is high.
LED-BAR AND LED-BAR DRIVER
For visual read-out of aerial power and RF-gain, a 10 segment LED bar with driver, i.e. U01 and U02, is
used. The two signals are added in D01 and D02, and through the filter R01, R02 and C02 passed on to
U02, pin 5. +5V on U02, pin 6 is reference for the signal. The individual segments in the LED bar are turned
on by a rise in the signal of 500 mV.
The brightness of the LED bar is controlled by bits 4 and 5 in the 8 bit serial register U06. The adjustment
follows the 4 steps, which also apply to brightness in the display. In order to be able to switch off the LED
bar completely, Q01 is set off when U06, bits 4 and 5 are high.
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