topic KBI question in 8-bit Microcontrollers

KBI question

Hsin — Wed, 28 Jul 2010 03:01:59 GMT

Hi,

I am trying to run the basic KBI function on processor expert. I use DEMO9S08LL16 demo board. The goal is to make the variable "state" increase 1 when KBI activated every time. I use PTA pin 7 for KBI. However, I got cpu_interrupt when I push the button (KBI activate) in the first time. I could not figure out what happen. Please advice.

Thanks much.

I attached my code in the attachement.

Re: KBI question

ProcessorExpert — Fri, 30 Jul 2010 03:02:05 GMT

Hello,

it is not Processor Expert issue, it is rather application issue. Please check attached example of using Init_KBI component to initializace KBI registers including proper allocation of interrupt vector. I thing the example can be easily modified to provide functionality you need.

best regards
Vojtech Filip
Processor Expert Support Team

Re: KBI question

Hsin — Mon, 09 Aug 2010 06:54:58 GMT

Hello,

Thanks much for your support.

Re: KBI question

Lundin — Mon, 09 Aug 2010 20:28:33 GMT

//clear KBF
KBISC_KBACK = 1; // wrong bit??

Well... you could try to do what your comment says and clear KBF bit (flag) rather than some acknowledge flag.

KBISC_KBF = 1;

If you have an actual mechanical button you must also add a timer for debouncing the signal.

Re: KBI question

bigmac — Tue, 10 Aug 2010 07:13:09 GMT

Hello Lundin,

For the device in question, and other HCS08 devices, the KBACK bit is a write only bit used for clearing the the KBF flag. According to the reference manual, writes to KBF have no effect.

I agree with the need to debounce a mechanical switch.

Regards,

Mac

Re: KBI question

Lundin — Tue, 10 Aug 2010 18:01:21 GMT

Oops I should probably check the manual before posting. In that case the only issue is that the isr wasn't included in the vector table, as already mentioned.