IRQ Issue with Arduino UNO + Ethernet Shield + PS/2 Keyboard

Projects General Guidance
1

Hi,

I am having trouble using the PS/2 Keyboard library with the Ethernet shield attached. I have tried it without the shield and it works fine using the allowed IRQ pins 2 and 3 but with the shield it seems that it is unable to read the keyboard input. The IRQ allowed pins, according to the library, are 2 and 3. The data pin it seems can be any digital pin, I have tried using 7, 2 and 5 but that didn't help.

Symptoms:

Keyboard lights flash (Normal on the working sample sketch without the shield)
No response to keyboard input with the Ethernet shield attached.

I can only assume that it is an IRQ pin problem and that the Ethernet shield is using those pins.

It is integral to my project that I use an Ethernet shield, does anyone have an suggestions on the IRQ problem?

Thanks,

David

2

IIRC some ethernet shields have a possibility to cut the IRQ line on the bottom side of the PCB. It uses pin 2 (?) to indicate there is data received.

That means that pin3 should be free for your KB.

Check shieldlist.org to see whcih pins your ethernet shield uses.

3

Hmm, I thought the same so I tried pin 3 for the IRQ and another pin for the Data but the keyboard.available() is still not picking it up.

I have used a couple of serial.print statements within the test sketch to see at which point the program stops, it just never is able to see the keyboard with keyboard.available.

4

Does anyone know if it would be possible to create a new interrupt pin and allow the PS2Keyboard library to use that?

5

Check this one - Arduino Playground - PinChangeInt -
ANy pin can generate an interrupt but you have to add some logic to determine the pin

6

Thanks for that.

I just had a quick read and I think I get it.....

I don't really know what kind of interrupt the ps2keyboard library expects to use, RISING, FALLING or CHANGE. I guess I will just have to have a go. I have ordered a rev3 2560 mega because it has more external interrupts which is pretty lazy.

I will give this a go tonight.

7

hi David, i have the same problem... can you help me?