[OpenWrt-Devel] Is "using gpio to simulate I2C bus" robust on AR9331?

Hartmut Knaack knaack.h at gmx.de
Thu May 4 17:18:36 EDT 2017


Xuebing Wang schrieb am 04.05.2017 um 03:19:
> Hi community,
> 
> I am using Atheros AR9331 + OpenWRT Chaos Calmer 15.05 on a commercial 
> product.
> 
> I've used I2C on many projects, all with dedicated I2C controllers. I've 
> never used GPIOs to simulate I2C on Linux.
> 
> I may be wrong, I am tending to think that there is no way to generate 
> good I2C waveforms by using 2 GPIOs (SCL/SDA), except that we disable 
> all interrupts and maybe using high precision timer when outputing SCL/SDA?
> 
> Is "using gpio to simulate I2C bus" robust on AR9331?
> 

I have been using a GPIO extender connected via I2C to a router powered by
an AR9132 (should be close enough), running for months without notable issues.
In that case, I2C traffic was pretty low, it just had to access the GPIOs of
the extender a couple of times per hour. It has been way better than using an
I2C-Tiny USB adapter, but that would be a different story.

> Thanks.
> Xuebing Wang
> _______________________________________________
> openwrt-devel mailing list
> openwrt-devel at lists.openwrt.org
> https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
> 

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