LIN connectivity

[aladdin83]

Hi all,,

I am using a PIC16F877A microcontroller and I am using both of the PWM/Capture/Compare pins to send out a PWM signal.

To continue working on the project I need to measure speed which can be done using Capture command but since I am out of Capture/Compare pins I am thinking about adding another microcontroller chip like PIC12F for example.

does anyone have an idea on how to connect the two chips together to make the PIC16F my master ucontroller and the PIC12F my slave ucontroller.

I read in the microchip website that there is protocol called LIN but I didnt find much info on how to start, how to connect or how to program the two PICs

so if anyone have any resources or advice regarding the LIN connectivity I would really appreciate your help

thank you

 

[Nigel Goodwin]

Just connect them with a simple asyncronous connection, using either two pins (one each way), or even just one pin can be used if required.

 

[Pommie]

You might be able to measure speed with the timers. You could count using timer 0 and use timer 1 as the timebase.

Mike.

 

[aladdin83]

Just connect them with a simple asyncronous connection, using either two pins (one each way), or even just one pin can be used if required.

could you explain more cause I dont have much experience,,
and sample code would be very helpful

thanks

 

[aladdin83]

You might be able to measure speed with the timers. You could count using timer 0 and use timer 1 as the timebase.

Mike.

I thought timer 1 is used for the PWM already?

 

[Pommie]

PWM uses timer 2.

Mike.

 

[aladdin83]

PWM uses timer 2.

Mike.

i see

when i was looking at the manual, i thought i cant use timer 0 and timer 1,,

how do i write the code for it ?

 

[Nigel Goodwin]

could you explain more cause I dont have much experience,,
and sample code would be very helpful

thanks

Check my tutorials which show how to do RS232 - you don't need MAX232's between PIC's, just pin to pin.

 

[Pommie]

i see

when i was looking at the manual, i thought i cant use timer 0 and timer 1,,

how do i write the code for it ?

That depends on the pulse rate from the encoder. If it's slow (100/S) then you use timer 1 to time each pulse. If faster then you clock timer 0 with it and use timer 1 to produce a (eg) 10mS interrupt to process timer 0 counts.

Mike.

 

[aladdin83]

Check my tutorials which show how to do RS232 - you don't need MAX232's between PIC's, just pin to pin.

thanks for the website, but i didnt understand how to use the RS232 between the microcontrollers

i found away using I2C interface which doesn't require any additional IC for the interface and I think it's supported by the PIC16F877A that I'm using

 

[aladdin83]

That depends on the pulse rate from the encoder. If it's slow (100/S) then you use timer 1 to time each pulse. If faster then you clock timer 0 with it and use timer 1 to produce a (eg) 10mS interrupt to process timer 0 counts.

Mike.

Thanks, I didnt know that I can use these timers,, I will read more about the timers and see if it works, if not I will use two ucontroller IC's

Thanks again

 

[Nigel Goodwin]

thanks for the website, but i didnt understand how to use the RS232 between the microcontrollers

i found away using I2C interface which doesn't require any additional IC for the interface and I think it's supported by the PIC16F877A that I'm using

So you can't figure out simple RS232, yet you can complicated I2C?.

All you do for serial between PIC's is connect TX to RX, RX to TX, and the grounds together (which would be anyway).

 

[aladdin83]

So you can't figure out simple RS232, yet you can complicated I2C?.

All you do for serial between PIC's is connect TX to RX, RX to TX, and the grounds together (which would be anyway).

it's not that I can't figure out a simple RS232..
it's just that I havent worked with PICs before starting this project and I've been using PIC BASIC Pro compiler and the codes are different from what you are using in your tutorial and the manual for the pic plus the compilers manual are more clear to me...

thanks anyway,