ELCOM Euro-50, Руководство по обслуживанию

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Euro-50 Service manual
47
Elcom s. r. o.
5.9. Keyboard
A part of the keyboard is a component of the motherboard - the contacts (carbon pads) on its underside. The buttons
of the rubber keyboard have from their underside a carbon layer which upon pressing of the button, connects to a
contact on the dps. The buttons are electronically connected in a matrix of 7 columns and 5 rows.
Cashier keyboard: Cyclical awakening of always one column (set to H) and reading the state of the rows (RW0 to RW4).
After pressing a key, H is detected in the given row. For awakening the columns, multiplexor 74HC4051 (DD1) is used.
5.10. Interface for connecting displays
The displays are connected to the I2C0 bus of the microcontroller. Supported is a character (2 x 16 characters) and
10-place 7-segment display. The FFC cable of the cashier display (character) is connected to connector XC2 on the
motherboard. The customer display is connected to the dps display interconnect, which is connected to connector
XC3 on the motherboard.
Table 5.23. Signals of the interface for connecting the cashier display - XC2
XC2 Signal Description
1 VLCD Supply voltage for LCD
2 GND Relative potential
3 VDDQ Supply voltage for electronic display
4 VDDQ SA0 - zero bit I2C slave address of display
5 DISPDATA-1 I2C DATA
6 DISPRST1-1 Input of external reset signal
7 DISPCLK-1 I2C CLK
Table 5.24. Signals of the interface for connecting the cashier display - XC3
XC3 Signal Description
1 VDDQ-XC3 Supply voltage for the display
2 GND-XC3 Relative potential
3 DISPDATA-2 I2C DATA
4 DISPCLK-2 I2C CLK
5 GND-XC3 Relative potential
6 DISPRST2-1 Output of external reset signal
5.11. The RS232 interfaces, USB Slave
The interfaces RS232 - COM1, COM2 utilize the UART interfaces of the microcontroller marked UART0 and UART1.
The signals RXD0, TXD0 of port UART0 are brought through the inverter on the level RS-232 UU2, ZT3222LEEY to the
outputs of connector XC12 as signals RXD0-232-1, TXD0-232-1. (COM1).
The signals RXD1, TXD1 of port UART1 are brought through the inverter to the level RS-232 UU2, ZT3222LEEY to the
outputs of connector XC13 as signals RXD1-232-1, TXD1-232-1. (COM2).
The interface USB slave is realized through an internal USB by controller of the microprocessor DM1, which contains
a physical and a data layer for direct connection to the USB peripheral and satisfies the specifications of USB2.0. The
signals are led out to connector XC5.
Table 5.25. Signals for interfaces COM1 RS232 - XC12
XC12 Signal Description
1 EXT5V-XC12 Supply voltage for peripheral device - scanner
2 GND-XC12 Relative potential
3 RXD0-232-1 COM1 RXD
4 TXD0-232-1 COM1 TXD