Instructions

18Hardware

means that measured voltages can be represented by integral numbers from 0 through 1023. The ref-

erence voltage for the lower limit is GND level, i. e. 0V. The reference voltage for the upper limit can

be selected by the user:

5V Operating Voltage (VCC)

Internal Reference Voltage of 2.56V

External Reference Voltage e. g. 4,096V generated by a Reference Voltage IC.

If x is a digital measuring value then the corresponding voltage value u is computed as follows:

u = x * Reference Voltage / 1024

Clock Generation

Clock generation takes place by a 14.7456MHz Quartz Oscillator. All time dependent actions within

the controller are derived from this clock frequency.

Reset

A Reset initiates the return of the Micro Controller system to a defined starting condition. In gerneral

the C-Control Pro Module knows two reset sources:

Power-On-Reset: is automatically executed after switch on of the operating voltage.

Hardware-Reset: is executed when the Module’s RESET (Pin 9) is pulled to "low" and released

again by e. g. shortly pressing the connected reset key RESET1 (SW3).

A "Brown-Out-Detection" avoids that the Controller can enter undefined conditions in case of drop-

ping operating voltages.

Digital Ports (PortA, PortB, PortC, PortD)

The C-Control Pro Module provides four digital ports at 8 pins each. To the digital ports it is possible

to connect e. g. pushbuttons with pull-up resistors, digital IC’s, opto couples or driver circuits for re-

lais. The ports can be addressed either separatly, i.e. pin by pin or byte by byte. Each pin can either

be input or output.

Never connect two ports directly together which should simultaneously work as outputs!

Digital input pins are high-impedance or wired to internal pull-up resistors and transform an applied

voltage signal into a logical value. For this it is required that the voltage signal is within the limits

defined for TTL and CMOS IC’s high or low levels. During further processing in the program the lo-

gical values on the respective input ports are represented as 0 ("low") or 1 ("high"). Pins will take on

the values 0 or 1, Bytes from 0 to 255. Output ports are able to give out digital voltage signals by use

of an internal driver circuit. Connected circuits can draw (at high level) or feed (at low level) a specific

current from or to the ports.

Pay attention to the maximum admissable load current for a single port or for all ports in total.

Exceeding the maximal values may lead to destruction of the C-Control Pro Module. After a reset

each port is initially configured as input port. By certain commands the direction of data transport

can be toggled.