[Tinyos-help] Tinyos-help Digest, Vol 65, Issue 3

[KURT PETERS]

Axel,
   What version of TinyOS are you using?  There was a thread about a year 
ago about problems with the way I2C was implemented (check under my name), 
if you're using 2.x.  The new version (release) seems to have the fix 
implemented.
Regards,
Kurt

----Original Message Follows----
From: Axel Poigné <axel.poigne at iais.fraunhofer.de>
To: tinyos-help at millennium.berkeley.edu
Subject: [Tinyos-help] Puzzled about I2C write
Date: Mon, 1 Sep 2008 18:48:16 +0200
Hi

I am trying to use the I2C bus to read and write an EEPROM but failed.  It 
seems the write does not work. I went into the code and I am  puzzled about 
the following piece of code in tos/chips/msp430/usart/ Msp430I2CP.


void nextWrite() {
     if ( ( m_pos == m_len - 1 ) && ( m_flags & I2C_STOP ) ) {
       call HplI2C.setStopBit();
     }
     else if ( m_pos == m_len ) {
       signalDone( SUCCESS );
       return;
     }
     call HplI2C.setData( m_buf[ m_pos++ ] );
   }

It seems that it never gets into the success branch: the stop bit is  set 
but there is no further interrupt coming. If I understand the I2C  correctly 
this makes sense since after writing all the bytes an  acknowledge (hence 
interrupt) should be issued by the slave, and then  the master should send 
the stop bit.

I wonder whether I am mistaken or if my EEPROM goes wrong. The EEPROM  I use 
is a Microchip 24LC64 on a custom-build board (where MSP and  CC2420 runs 
fine).

Axel