PEP CP380 Manual page 21

CP380
Operation with Interrupt: 16 digital inputs and 2 interrupt channels
In this operation mode the 8255 PIO device is configured for mode 1. Two input groups
(group A and group B) each containing an 8 bit data port and a 4 bit control/data port are
available. The 8 bit ports are used for data input. The CP380-I uses only the PC4 (inter-
rupt input for port A) and PC2 (interrupt input for port B) control port lines. All input ports
are latched.
1.7.1.2 CP380-O
The CP380-O is implemented so that the ports A and B use the 8255 for simple data
output (16 outputs). There is no interrupt control available on the CP380-O board.
1.7.1.3 CP380-I/O
The CP380-I/O operation is configured by software. Two operational modes of the 8255
device are used by the CP380-I/O.
Operation without Interrupt: 8 outputs and 10 inputs
In this operation mode, port A is used for data output and ports B and C are used for
data input. Data is written to, or read from, the chosen port, and no handshaking is
required. By configuring the 8255 for mode 0, one output port (port A: 8 bit wide) and
two input ports (port B, 8 bit wide; port C, 2 bit wide) are available.
Operation with Interrupt: 8 outputs, 8 inputs and 1 interrupt channel
In this operation mode, port A of the 8255 is configured for mode 0 and port B is config-
ured for mode 1. Port A (8 bit output) and port B (8 bit input) are used as data ports. The
PC2 line of port C is used as the interrupt control line for port B. The PC4 input is not
used.
1.7.2 Wiring
The inputs and outputs of the various boards are electrically isolated by optocouplers.
There is no electrical connection between the hardware connected to the board and the
PC.
ID 19313, Rev. 0100 ® PEP Modular Computers GmbH
Introduction
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