Closing i2c after use

[Richard Chapman]

Hi All

I have a simple program on a raspberry pi4 to read from an eeprom over i2c, after reding the data I have the following in my code:-

 bcm2835_i2c_end();
 bcm2835_close();

The c code complies and executes as intended, however if I then run

sudo i2cdetect -y 1

The command runs really slow and nothing is detected on the i2c port. It's like my c code isn't closing the port. If I reboot and then run sudo i2cdetect -y 1 everything is back to normal. Any ideas?

Thanks

[Sean ONeill]

Hi

The bcm2835 library works directly on the SPI/I2C devices. It is not using any Linux device drivers. When relevant Linux drivers are loaded or activated then it can create unexpected behavior from other software like 'i2cdetect'.

Here is a simple utility which detects I2C bus devices with the bcm2835  library.
https://github.com/gavinlyonsrepo/RPI_Tools/tree/main/src/i2cdetect

[Mike McCauley]

Thanks for mentioning this Sam,

I have added a link to that utility for the next version

Cheers.

On Monday, 12 February 2024 00:59:18 AEST Sean ONeill wrote:
> Hi
>
> The bcm2835 library works directly on the SPI/I2C devices. It is not using
> any Linux device drivers. When relevant Linux drivers are loaded or
> activated then it can create unexpected behavior from other software like
> 'i2cdetect'.
>
> Here is a simple utility which detects I2C bus devices with the bcm2835
> library.
> https://github.com/gavinlyonsrepo/RPI_Tools/tree/main/src/i2cdetect
>
> On Thursday, February 8, 2024 at 11:33:55 AM UTC nood...@gmail.com wrote:
> > Hi All
> >
> > I have a simple program on a raspberry pi4 to read from an eeprom over
> > i2c, after reding the data I have the following in my code:-
> >
> >
> >

> > * bcm2835_i2c_end(); bcm2835_close();*

> >
> > The c code complies and executes as intended, however if I then run
> >

> > *sudo i2cdetect -y 1*

> >
> > The command runs really slow and nothing is detected on the i2c port. It's

> > like my c code isn't closing the port. If I reboot and then run *sudo
> > i2cdetect -y 1 *everything is back to normal. Any ideas?
> >
> > Thanks


--
Mike McCauley VK4AMM mi...@airspayce.com
Airspayce Pty Ltd 9 Bulbul Place Currumbin Waters QLD 4223 Australia
http://www.airspayce.com 5R3MRFM2+X6
Phone +61 7 5598-7474

[Richard Chapman]

Hi All

Ah, that makes sense, thanks for the information.