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why my I2C register don't change

 
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sanshiroo



Joined: 20 Apr 2014
Posts: 4

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why my I2C register don't change
PostPosted: Mon Apr 21, 2014 7:29 pm     Reply with quote
Now I use function i2c, but when I debug program for check register value the register SSPCON SSPCON2 SSPSTAT value is 0x00 don't change value.
Why the register don't change value?

This is my code
Code:

#include <16F886.h>
#use    I2C(master,sda=pin_c4,scl=pin_c3)
void main()
{
   i2c_start();
   i2c_write(0xD0);
   i2c_write(0xff);
   i2c_stop();

}


thank a lot
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Mon Apr 21, 2014 8:20 pm     Reply with quote
Quote:
#use I2C(master,sda=pin_c4,scl=pin_c3)
SSPCON SSPCON2 SSPSTAT value is 0x00 don't change value.

Download the CCS manual and read the #use i2c() section:
https://www.ccsinfo.com/downloads/ccs_c_manual.pdf
It says:
Quote:
Software functions are generated unless FORCE_HW is specified.
sanshiroo



Joined: 20 Apr 2014
Posts: 4

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PostPosted: Mon Apr 21, 2014 8:59 pm     Reply with quote
PCM programmer wrote:
Quote:
#use I2C(master,sda=pin_c4,scl=pin_c3)
SSPCON SSPCON2 SSPSTAT value is 0x00 don't change value.

Download the CCS manual and read the #use i2c() section:
https://www.ccsinfo.com/downloads/ccs_c_manual.pdf
It says:
Quote:
Software functions are generated unless FORCE_HW is specified.


thank a lot

And what is the difference of use FORCE_HW and don't use
Ttelmah



Joined: 11 Mar 2010
Posts: 19480

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PostPosted: Tue Apr 22, 2014 12:28 am     Reply with quote
Because it doesn't use the hardware (so no registers changing...).

It generates extra code, to produce a software I2C emulation driver. Slower, bulkier, can only do 'master', but has the advantage it can be used on any pins, and on the PIC's that don't have hardware - hence the reason this is the default.
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