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nono240

Reged: Feb 09 2005
Posts: 76
Loc: FRANCE

[PIC18] Interrupt-Driven I2C Routines (100% C Version)
#18597 - Thu Aug 25 2005 03:12 AM Attachment (2173 downloads)

I've implemented the G.Neiss's code in 100% C for my 18F8722.

It's *ALMOST* the same except 16 bit device's address is not implemented since it was useless for me (but VERy easy to implement).

Don't forget the interrupt routine :

Code:
--------------------------------------------------------------------------------

//---------------------------------------------------------------------//
//-------------------------Low priority Interrupt----------------------//
//---------------------------------------------------------------------//
void interrupt low_priority lowISR()
{

//-------------Interrupt on I2C events----------------//
if(SSP1IF && SSP1IE)
I2Cmachine();

}

--------------------
In a world without walls nor Windows, who needs Gates ?

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G.Neiss

Reged: Dec 26 2004
Posts: 474
Loc: germany

Re: [PIC18] Interrupt-Driven I2C Routines (100% C Version) [Re: nono240]
#18600 - Thu Aug 25 2005 05:02 AM

It's a good 'reverse engeniering' of my assembler code

I would use it as a base point for implementing I2C on other processors.
Why ?
Look at the generated code and You will see, the assembler only version is faster.
But of course it's not portable.
So thanks for translating it.

ciao
Guenter

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nono240

Reged: Feb 09 2005
Posts: 76
Loc: FRANCE

Re: [PIC18] Interrupt-Driven I2C Routines (100% C Version) [Re: G.Neiss]
#18612 - Thu Aug 25 2005 09:11 AM

Quote:

It's a good 'reverse engeniering' of my assembler code

Quote:

Look at the generated code and You will see, the assembler only version is faster.

Sure ! Assembler is ALWAYS faster.
This version is for 'educational' purposes -> "I2C for newbies"

Quote:

But of course it's not portable.

Sure too...

Quote:

So thanks for translating it.

Thanks to you for your original code.

--------------------
In a world without walls nor Windows, who needs Gates ?

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2171984

Reged: Oct 14 2005
Posts: 1

Re: [PIC18] Interrupt-Driven I2C Routines (100% C Version) [Re: nono240]
#19351 - Fri Oct 14 2005 11:21 PM

thanks

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dimithri

Reged: Oct 16 2005
Posts: 1

Re: [PIC18] Interrupt-Driven I2C Routines (100% C Version) [Re: 2171984]
#19368 - Sun Oct 16 2005 04:25 AM

hello since we're on the topic I thought of asking this...

I'm having trouble with a project i've undertaken recently where i am trying to interface a Anybus module to a PIC18f452. Everything was going fine until i found that I don't have enough I/O pins to address the Anybus module's 12bit address. Therefore I wanted to use a PCF8575 I/O expander chip which uses I2C interface. But I'm already using the pins SCL and SDA pins for the DAC which I use (its interfaced using the SPI interface) hence I've got a problem. I'm already using PORTD an PORTE for the Parallel Slave Port (PSP) to get data to the Anybus and PORTA is used for the Analog to Digital converter and I only have PORTB (8bits) left. I've tried to implement a latching system where i address the 12bits with 8bits by de-multiplexing but its very complex. I'm using the PIC18f452 chip as stated before with MICRO CHIP MPLAB C18 compiler.

Hope somebody can help..
Thanks,
regards, Dimithri

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Dan Henry
Guru

Reged: Oct 16 2003
Posts: 3856
Loc: Colorado

Re: [PIC18] Interrupt-Driven I2C Routines (100% C Version) [Re: dimithri]
#19375 - Sun Oct 16 2005 11:20 AM

A few ideas:

Have SPI and I2C devices share the MSSP pins. Although I have never tried it, apparently some have done it. For example, see Mixing I2C and SPI on the same pins.
Implement I2C in software on available GPIO pins (i.e., bitbang).
Move your DAC's SPI interface to available GPIO pins in implement SPI in software (i.e., bitbang), since bitbanging SPI is (arguably) easier than bitbanging I2C, and put the I/O expander on the MSSP's hardware I2C pins and switch the MSSP to I2C mode.

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Bolt

Reged: Oct 29 2003
Posts: 48
Loc: The Netherlands

Re: [PIC18] Interrupt-Driven I2C Routines (100% C Version) [Re: Dan Henry]
#21527 - Wed Mar 01 2006 06:21 AM

Change the DAC to an I2C version?... Use the I/O expander and the DAC on the I2C bus...

--------------------
Marko
eMbed Engineering

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jlian168
stranger

Reged: Mar 31 2009
Posts: 1

Re: [PIC18] Interrupt-Driven I2C Routines (100% C Version) [Re: nono240]
#104312 - Tue Mar 31 2009 04:35 AM

Deal sir:
Pardon me,My english not well.
I've a question for you?
I use the the I2C interrupt routine in PIC16F877A & DS1307,
But not stable,Because some time is good and sometime is bad!I don't know why?
//
1.DS1307 no connect Battery.
2.use SDA RC4 & SCL RC3(all pull-high)
3.MPLAB V8.10
4.PICC16 V9.6 std
5.cpu XTAL=4MHz
6.DS1307 xtal=32.768kHz
//
Could you help me?
Thanks you very much.
Have a nice day.
/*************************************************/
2009/04/02:
Now i think it may be no ack by battery no connect!
Because i connect the battery is running good.
/*************************************************/

Edited by jlian168 (Thu Apr 02 2009 12:01 AM)

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