Conrad C-Control Pro Mega Series, Руководство пользователя

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38 Hardware
© 2008 Conrad Electronic
There are 5 light emitting diodes (LEDs). The LD3 (green) is located on the front below the DC
terminals and lights up when supply voltage is applied. LD4 and LD5 indicate the status of the USB
interface (see Section USB). The green LEDs LD1 and LD2 are located next to the four push
buttons and are freely available to the user. They are connected to VCC through a dropping resistor.
By means of jumpers LD1 can be connected to PortG.3 and LD2 to PortG.4. The LEDs will light up
when the corresponding pin port is low (GND).
Push Buttons
There are four push buttons provided for. SW3 (RESET1) will initiate a reset with Mega128 while
SW5 (RESET2) will do the same with Mega8. The push button SW1 and SW2 are freely available to
the user. Through jumpers SW1 can be connected to PortE.4 and accordingly SW2 to PortE.6.
There is the possibility to connect switches SW1/2 to either GND or VCC. The possibilities to
choose from are determined by
JP1 and JP2 resp. In order to have a defined level at the input port
while the push button is open the corresponding pull-up should be switched on (see Section
Digitalports ).
Pressing SW1 during power-up of the board will activate the Serial Bootloader Mode .
LCD
An LCD module can be plugged onto the application board. It displays 2 lines at 8 characters each.
In general also differently organized displays can be operated through this interface. Each character
consists of a monochrome matrix of 5x7 pixels. A flashing cursor below any one of the characters
will indicate the current output position. The operating system provides a simple software interface
for output on the display. This display is connected to connector X14 (16 poles, double row). By
means of a mechanical protection a faulty connection and thus the confusing of poles is avoided.
The LCD module used is of type Hantronix HDM08216L-3. Further information can be found on the
Hantronix Webseite
http://www.hantronix.com and in the data sheet list on the CD-ROM.
LCD Contrast (LCD ADJ)
Direct frontal view will allow best readability of the LCD characters. If necessary the contrast must be
trivially re-adjusted. The contrast can be adjusted by means of potentiometer PT1.
Keyboard
For user inputs a 12 character keyboard ( 0 .. 9 , * , # ) is provided (X15: 13 pole connector). The keyboard
is organized 1 out of 12, i. e. there is one line assigned to each key. The keyboard information is
read-in serially through a shift register. If no keyboard is used the 12 inputs can be used as
additional digital inputs. The keyboard uses a 13 pole terminal (single row) and is plugged to X15 in
such a way that the keys will point towards the application board.
With activating the PL (parallel load - KEY-E) input of the 74HC165 all 12 keyboard wires are
transferred in the 74HC165 shift register. After that all information bits are latched to Q7 with
triggering of CP (clock input - EXT-SCK). There they can be read with the EXT-Data Port. Since one
74HC165 holds only 8 Bit information, Q7 of the 1st 74HC165 is connected with DS of the 2nd