AT/PS2 Keybord - PIC Interface?

[sougata]

Hi,

I used it on a 40MHz oscillator and did not have any issue. However the following may be considered:

1. Allow enough time (2 seconds or more is safe) before calling the PS2init routine. Your keyboard needs this to boot-up. Indicated by all three LEDs flashing and going off.

2. The characters are stored using interrupts but the interrupts are re-enabled only when parse it. This may cause the keyboards internal buffer to be overwhelmed.

[BobPigford]

Thank you sougata,

Hi,

I used it on a 40MHz oscillator and did not have any issue. However the following may be considered:

1. Allow enough time (2 seconds or more is safe) before calling the PS2init routine. Your keyboard needs this to boot-up. Indicated by all three LEDs flashing and going off.

2. The characters are stored using interrupts but the interrupts are re-enabled only when parse it. This may cause the keyboards internal buffer to be overwhelmed.

I did allow enough time for the keyboard to start. I see the LEDs flash, so I think that is not the issue.

I will follow you suggestion and look into the buffer situation. I will also order a 40mhz oscillator just to be sure.

I will report back on my progress.

Thank you again,
Bob Pigford
Newark, Delaware, USA

[BobPigford]

Thank you sougata,



I did allow enough time for the keyboard to start. I see the LEDs flash, so I think that is not the issue.

I will follow you suggestion and look into the buffer situation. I will also order a 40mhz oscillator just to be sure.

I will report back on my progress.

Thank you again,
Bob Pigford
Newark, Delaware, USA

I just isolated the issue! If I eliminate any output going TO the keyboard, everything works just fine! I disabled the "putkey" routine buy placing a "RETURN" immediately after the beginning of the routine.

Even with the internal oscillator at 8mhz, it all works very well (even with "TOcntDLY set back to 10)! I can live without seeing the LEDs on the keyboard for now. When my 40mhz oscillator arrives, it will try it again and report back.

Regards,
Bob

[sougata]

Hi,

Every PIC18 has got a x4 HSPLL oscillator mode. So you can use an external 10MHz crystal to effectively get 40 MHz Fosc. For internal 8MHz you need to configure osccon to enable HSPLL and get 8 x 4 = 32MHz from the internal oscillator.

[BobPigford]

Hi,

Every PIC18 has got a x4 HSPLL oscillator mode. So you can use an external 10MHz crystal to effectively get 40 MHz Fosc. For internal 8MHz you need to configure osccon to enable HSPLL and get 8 x 4 = 32MHz from the internal oscillator.

Thank you Sougata. I will give this a try and report back. And thank you for teaching me about HSPLL.
Regards,
Bob