Principle Of Data Transmission; Interface To The Station - Conrad I/O-TERMINAL Bedienungsanleitung

C-Control I/O Terminal

Principle of Data Transmission

Interface to the STATION

Although ready-to-use drivers are available for all functions of the IOT, and the user, therefore, does
not necessarily have to know exactly how the interface works, a short description of the basic
operation principle is given in the following.
Communication between the control unit and the I/O Terminal is facilitated by a bus connection that
is used commonly by LCD and IO extension unit, the bus to the LCD being a IIC-Bus, the one to the
IO extension unit a serial, synchronous bus which does not require a special log.
Consequently, the following instructions and peculiarities have to be heeded for programming.
Writing on the LCD:
The BASIC driver will generate a log (IIC) while writing on the LCD, so that you will not have to
acquire special logging knowledge.
All data transmitted to the LCD will simultaneously be sent to the IO extension unit (common bus!),
which they actually were not addressed to.
Nevertheless, this will not lead to indication errors, since the data addressed to the IO extension do
require a STROBE signal to become effective first.
Writing on the IO extension unit
Again it is the driver that takes on transmission tasks. You merely have to take care that the two Byte
data set, which is directed to the IO extension unit contains correct information on the number of
ports and LED indicators.
Of course, these data will be communicated to the LCD at the same time. This again will not lead
to indication errors, since data are not logged and are therefore ignored by the LCD.
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