Re: [ECOS] TWI/I?C driver for AT91

[Jürgen Lambrecht <Jurgen dot Lambrecht at tiscali dot be>]

Andrew Lunn wrote:
> > Thanks for the heads up. I had noticed there are no DMA channels to
> > the TWI controller, but didn't think it would be much of an issue.
> > I'll give it a try and see where it takes me. I need I2C anyway, so
> > using the eCos framework makes some sense.
>
>
> If hardware I2c causes you problems you could always do bit banging
> using the same pins, but as GPIO lines. There is a bit banging
> framework in eCos.
We use the bit banging interface of ecos for I2C. Because an i2c transfer 
blocks the processor, you can not use i2c too fast, or it could disturb 
other threads. Be aware that i2c is slow, so a transfer takes a relatively 
long time, blocking the processor.
For us this is OK, as we only use it for initializations.

Maybe it is a better idea to use  for i2c the timer pins of the TC 
controller with PWM support, and then write your own driver for it. I 
guess this will have the same performance as using the TWI controller.

Kind regards,
Juergen

>       Andrew

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Jürgen Lambrecht
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