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GCA128L pushbutton testboard for I/O units


By Peter Giling


The board connects with the standard 10 Pin PSK connecter to the GCA50, CAN-GC2 or GCA_PI02.
Two connectors are provided, which are internally connected together.
This enable to put he GCA128L in between the testing area.
It fits in a standard box
The interface is set-up as a test-unit for a new assembled I/O unit in the various systems.
The resistors R1..R8 are basicly not needed for the function, a direct wiring will do as well,
But the reason why these resistors are installed is that with testing an GCA50 / CAN-GC2 / GCA_PI02 unit, any of the connected I/O could be programmed as output,
so in that case activating the push button could damage the chip on the GCA50 / CAN-GC2 / GCA_PI02 unit.
The resistor prevends that.

At any port, when it is activated as output, pressing the button has no effect.
GCA128L is provided with Bus driver 74HCT245.
This makes sure that leds give a real picture of the logical state the I/O ports are in.
Inputs will always show with green led, because a free input is always in high state.

Led indication

Red and green leds of each port are interconnected in a way that when port = high, green led shows,
and when port is low, red led is lit.

The hardware

This board is available, and also kit , with or without box.

N.B. Only complete ordered kits are supported!


Connector J1 and J2 are interconnected.
This enables the use of GCA128L in between the I/O unit and Input/Output driver.

Led indication.

Port 1 HIGH LR1 = OFF LG1 = ON
Port 1 LOW LR1 = ON LG1 = OFF
Port 2 HIGH LR2 = OFF LG2 = ON
Port 2 LOW LR2 = ON LG2 = OFF
Port 3 HIGH LR3 = OFF LG3 = ON
Port 3 LOW LR3 = ON LG3 = OFF
Port 4 HIGH LR4 = OFF LG4 = ON
Port 4 LOW LR4 = ON LG4 = OFF
Port 5 HIGH LR5 = OFF LG5 = ON
Port 5 LOW LR5 = ON LG5 = OFF
Port 6 HIGH LR6 = OFF LG6 = ON
Port 6 LOW LR6 = ON LG6 = OFF
Port 7 HIGH LR7 = OFF LG7 = ON
Port 7 LOW LR7 = ON LG7 = OFF
Port 8 HIGH LR8 = OFF LG8 = ON
Port 8 LOW LR8 = ON LG8 = OFF

Please consider that portnumbers are only examples, the real portnumber will have different Address.

mgv128-en.txt · Last modified: 2018/11/12 08:56 (external edit)