PIC 18F device suggestion.

[aratti]

Why not using a frequency to voltage converter and than use an ADC channel to read the car RPM.

Cheers

Al.

[srspinho]

Hi !

Hummmm... Can you Belive I Had never tryed This before !

I will make some research on converting frequency to voltage on a range from 0v to 5v.

Thank you for the advice !

[towlerg]

16f1526/7 has a whole bunch of timers.

Exactly how are the three timers on the 877 used? perhaps you can shuffle them and make it work with just software. I assume existing timer3 doesn't need a trigger input. Maybe 1 or 3 on the 2420 could be used as the timebase.

George

[srspinho]

Hi George,

thank you for the reply !

Well, I´m using all 16f877's as described bellow :

1) TMR0 => Count the number of pulses from the car's wheel.
2) TMR1/CCP1 => measure the Feel Injector's "On-Time"
3) TMR2 => This timer is used as a 500ms time base for all calculation and display update.

I´m using DT Interrupts to deal with the timers.

May be use the RB change pin interrup to count the RPM events.

I´m planning to move my project to the ST7735 display, and use the Richard libs available here in the forum. SO, I should move to a 18F series Pic.

I have here with me, some 18F2420, 18F4550 and 18F2520. I'll try to some of them.

My best regards !

Sérgio