[Tinyos-devel] inconsistency between Telos and MicaZ I2C addressing

[Xiaofan Jiang]

Right justification may be slightly more intuitive but I'm comfortable with either as long as it's clearly stated in the interface file. But it sounds like there is a strong feeling towards right-justification on the help thread. 

-Fred


----- Original Message -----
From: Philip Levis <pal at cs.stanford.edu>
Date: Thursday, September 20, 2007 1:00 pm
Subject: Re: [Tinyos-devel] inconsistency between Telos and MicaZ I2C addressing

> 
> On Sep 14, 2007, at 3:50 PM, Xiaofan Jiang wrote:
> 
> > Hi,
> >
> > I recently came across an inconsistency between Telos and MicaZ 
> I2C  
> > addressing scheme when I was porting my telos program to micaz.
> >
> > In Telos, the least significant 7 bits of the i2c address 
> argument  
> > is used whereas in MicaZ the most significant 7 bits is used.
> >
> > For example, to address an I2C device with the address 1010101, 
> in  
> > Telos, the command would be something similar to:
> >
> > call I2CPacket.write(I2C_START | I2C_STOP, 0x55, 1, &buff);
> >
> > but in MicaZ it would be:
> >
> > call I2CPacket.write(I2C_START | I2C_STOP, 0xAA, 1, &buff);
> >
> > It seems like those two should agree in one way or another.
> 
> Agreed -- the MSP430 and atm128 maintainers should figure this out. 
> 
> IIRC, Jonathan Hui wrote the MSP430 implementation, and I wrote the 
> 
> atm128.
> 
> As a programmer, which do you think was more intuitive, right- 
> justified or left-justified? I think I implemented the atm128 the 
> way  
> I did because that's how a datasheet wrote it.
> 
> Phil
>