Are these pull-ups used if I programm the I2C Interface using mraa?
As I remember for Edison Arduino board and Edison Miniboard pull-ups for I2C are disabled after I2C interface initialization using MRAA.
I strongly recommend to setup a pull-up configuration after I2C bus initialization.
You may change it as you need by using mraa_gpio_mode function after I2C initialization.
Are different pull-ups used depending on the bus speed?
It is possible to configure pull-ups as you need after changing a bus speed.
Are pull-ups used if I use the I2C Interface using system commands?
Yes, they are used in the state selected before you use system commands.
If you do not configure a pull-up state, a previous state is used.
Can you tell me what is the default state if I use the I2C interface?
I am working on a custom board and realized that external pull-ups must be a few kilos, also if I chose the high speed mode (which normally uses a pull-up around 1k ohm)
So it would be interesting if an external pull-up should be used, or if the internal values should be used depending on the bus speed.
Sorry for the late reply, I have been working on another important aspect of the board...
here is the command output:
root@Edison3Antenna:~# cat < /sys/kernel/debug/gpio
GPIOs 0-191, pci/0000:00:0c.0, 0000:00:0c.0:
gpio-61 (SW1UI4 ) in hi
gpio-64 (bcm43xx_irq ) in hi
gpio-71 (bcm_bt_lpm ) out hi
gpio-77 (sd_cd ) in hi
gpio-96 (vwlan ) out hi
gpio-124 (hsu ) in lo
gpio-125 (hsu ) out lo
gpio-126 (hsu ) in hi
gpio-127 (hsu ) out hi
gpio-128 (hsu ) in hi
gpio-129 (hsu ) in hi
gpio-130 (hsu ) in hi
gpio-131 (hsu ) in hi
gpio-132 (hsu ) in lo
gpio-133 (hsu ) out lo
gpio-134 (hsu ) in hi
gpio-184 (bcm_bt_lpm ) out lo
gpio-185 (bcm_bt_lpm ) in lo
root@Edison3Antenna:~# uname -a
Linux Edison3Antenna 3.10.17-poky-edison+ #2 SMP PREEMPT Wed Jun 15 11:13:10 CEST 2016 i686 GNU/Linux
With this output no external pull-ups are connected.
If you look at this: Exploring Edison - Beyond mraa
you can see that there are different onboard pull-ups that can be programmed. I suppose mraa does not use this option, does it?
This message was posted on behalf of Intel Corporation
If you look at the link you shared, at the beginning of the “Controlling the GPIO Mode”, there’s a note that says that not all the possibilities of changing GPIOs are available with MRAA.
There’s a thread with a similar discussion here https://communities.intel.com/thread/56312