Re: DS1307 on rpi4B

Hi,

> On 8 Dec 2024, at 12:35, 風來散人 <furaisanjin@gmail.com> wrote:
> I modified config.txt to load this dtbo and add one more line to set GPIO pins in [pi4]
> 
> gpio=12,13=a5,pu
> 
> This works fine and RTC starts working. One strange thing is that "gpioctl -l -v" doesn't show correct pin setting somehow. I assumed there should be PU on pin 12 and 13.
> 
> pin 12: 1       pin 12<>, caps:<IN,OUT,PU,PD,INTRLL,INTRLH,INTRER,INTREF,INTREB>
> pin 13: 1       pin 13<>, caps:<IN,OUT,PU,PD,INTRLL,INTRLH,INTRER,INTREF,INTREB>

Strange - I don't know if the pull ups on the SoC are suitable for I2C. The modules I have used have pull ups as real resistors - in internal pull-ups on SoCs tend to have a pretty broad range due to the way they are fabricated.

--
Daniel O'Connor
"The nice thing about standards is that there
are so many of them to choose from."
-- Andrew Tanenbaum