Instruction manual

32 SBC-400 User's Manual
4~6 D 20~22 5
6~8 C 22~24 4
8~10 B 24~26 3
10~12 A 26~28 2
12~14 9 28~30 1
14~16 8 30~32 0
External Switches and LEDs
Power LED and keylock (JP12)
You can connect an LED to indicate when the CPU card is on.
Pin 1 of JP12 supplies power to the LED and Pin 3 is the ground.
You can use a switch (or a lock) to disable the keyboard. In this
state the PC will not respond to any input. This is useful if you
don’t want anyone to change or stop a running program. Simply
connect the switch between Pins 4 and 5. The pin assignments
appear in the following table:
Power LED and keylock (JP12)
Pin Function
5 LED Power (+5 V)
4 No Connector
3 Ground
2 Keyboard lock
1 Ground
External speaker (JP13)
The CPU card has its own buzzer. You can disable the internal
buzzer and connect an external speaker to JP13. Enabling the
external speaker automatically disables the internal buzzer.