Real time clock + external interrupt in one PIC possible?

[HenrikOlsson]

Hi,
You don't have to use the 40-pin 18F45K22. You can use the 28-pin 18F25K22 with very minor changes to the code (CONFIG) or you can use another PIC - as long as it has a TMR1 & TMR2. But, if you want the code to run as-is then 45K22 it is.

If the distance per pulse is not 0.6m then you need to change the 39322 constant. For 0.61m it would be 39977 and for 0.59m it would be 38666 so as I think you can see you should be able to calibrate very accuratly. The final result will always suffer from truncation in the math routines so the display can be short as much as one count (0.6m or whatever distance one pulse equals) - which I don't think matters much.

/Henrik.

[Mugelpower]

Hello Henrik,

I guess I´m blind. In the first program you had RB6 as counter input. In the second program RB6 is the start-stop button. Where did the counter input go?

regards
Mugelpower

[HenrikOlsson]

On the 18F1320 (for which I tried to write the original program) the T1CKI is on RB6. On the 18F45K22 the T1CKI is on RC0.

/Henrik.

[HenrikOlsson]

Did you ever get it running on your end or did you loose interest?

I'm cleaning up my desk, can I put the dev board away?
It's best to ask because if I don't Murphy tells me there will be a new question, bug report or feature request tomorrow :-)

/Henrik.

[Mugelpower]

Hello Henrik,
no I´m not out of interest. I bought some 18F45K22 and 16Mhz crystal generators and then realized my PICKIT2 doesn´t support this device. I really appreciate your help and I´m astonishied about your speed. But I need some more time to get
into the hardware. I´ll realize that with a 18F1320 because i am already working on a project : a water pump, fuel pump and fan controller. I´m shure the configs for the speedo project will drive me crazy.

[HenrikOlsson]

If you look at this thread: http://www.microchip.com/forums/m540021.aspx I Think you'll find that you can get your PICKit2 working with the 45K22. If you don't wan't to mess around just get a PICKit3 from Digikey, Mouser or Microchip Direct and be done with it :-)

The timer code, as written, expects an 8MHz Clock, you'll need to change some things if you're using 16MHz, the CONFIG isn't one of them though. It should run fine with the CONFIG as posted.

/Henrik.

[Mugelpower]

Hello Henrik,

I´m stupid. Looked at the cristals and they were the right 8 MHz ones. Ordered the PICkit 3 yesterday so i can move along.