Because of not true_I2c bus I am afraid there are not open drain pins. Have a look at this:
PU/PD Resistance 200 kOm
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| Carambola2 I²C https://www.8devices.com/community/viewtopic.php?f=13&t=416 |
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| Author: | Felicitus [ 26 May 2013, 15:06 ] |
| Post subject: | Carambola2 I²C |
As Carambola2 lacks I²C support, I'm wondering if some of you already have solved this; for example, via SPI-I²C bridges. In particular, a device which is already supported by Linux would be very neat. Any ideas? Thanks Felicitus |
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| Author: | tty [ 27 May 2013, 10:03 ] |
| Post subject: | Re: Carambola2 I²C |
| Author: | Felicitus [ 27 May 2013, 10:08 ] |
| Post subject: | Re: Carambola2 I²C |
That's pretty neat, thank you for sharing! I originally thought that I need a SPI->i²C bridge, but that's elegant, too! |
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| Author: | old_europe [ 08 Oct 2013, 19:38 ] |
| Post subject: | Re: Carambola2 I²C |
| Author: | hutorny [ 12 Oct 2013, 15:26 ] |
| Post subject: | Re: Carambola2 I²C |
| Author: | tty [ 12 Oct 2013, 22:04 ] |
| Post subject: | Re: Carambola2 I²C |
| Author: | hutorny [ 13 Oct 2013, 04:51 ] |
| Post subject: | Re: Carambola2 I²C |
| Author: | tty [ 13 Oct 2013, 09:47 ] | ||
| Post subject: | Re: Carambola2 I²C | ||
Because of not true_I2c bus I am afraid there are not open drain pins. Have a look at this: PU/PD Resistance 200 kOm
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| Author: | hutorny [ 13 Oct 2013, 13:03 ] |
| Post subject: | Re: Carambola2 I²C |
| Author: | tty [ 13 Oct 2013, 16:25 ] |
| Post subject: | Re: Carambola2 I²C |
There is a 2.2K resistor on each I2C line. The lines are effectively pulled up to 3.3V, resulting in approximately 1.5 mA of pull-up current. A good rule of thumb is that if a downstream I2C device can sink more than 5 mA of current, the protocol should operate properly. I think there is no problem to stretch SCL, you can try it. |
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