Instructions

50Hardware

2.1.7 Mega128 Application Board

USB

The "C-Control Pro Application Board MEGA 128" (Conrad Item no. 198258) provides a USB inter-

face for the program’s loading and debugging. Because of the high data rate of this interface data

transmission times are considerably shorter compared to the serial interface. Communication

takes place through a USB Controller by FTDI and an AVR Mega8 Controller. The Mega8 provides

its own Reset push button (SW5). During USB operation the status of the interface is indicated by

two light emitting diodes (LD4 red, LD5 green). When only the green LED lights up the USB inter-

face is ready for operation. During data transmission both LEDs will light up. This also applies to

the Debug mode. Flashing of the red LED indicates an error condition. Is a program started in the

Interpreter, the red LED is turned on during the runtime. For USB communication the SPI interface

of Mega128 is used (PortB.0 through PortB.4, PortE.5), which must be connected by their re-

spective jumpers.

Note: Detailed information on the Mega8 can be found in the IC manufacturer’s PDF files on the C-

Control Pro Software CD-ROM.

On-Off Switch

The switch SW4 is located on the front of the application board and serves the power-up (On) or

power-down (Off) of the voltage supply.

Light Emitting Diodes (LED)

There are 5 light emitting diodes (LEDs). The LD3 (green) is located on the front below the DC ter-

minals and lights up when supply voltage is applied. LD4 and LD5 indicate the status of the USB in-

terface (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 Digital-

ports).

Pressing SW1 during power-up of the board will activate the Serial Bootloader Mode.

LCD