Lpc2000

Hello,

can you tell some more about the I2C reset, how this works. If it is 
possible that you can post you're code. I think some people on this 
group will thank you.

Thanks

Roy

--- In lpc2000@yahoogroups.com, "jim_e_dallas" <jim_e_dallas@y...> 
wrote:
> 
> Some erroneous I2C data on the bus can cause this condition. If an 
> I2C node sends a start condition with out a valid stop, then the 
I2C 
> interface will think the bus is busy and never generate the start 
> condition. When I write an I2C interface, I generally use a "switch
> (I2CSTAT)" with a case for each of the possible I2CSTAT states. 
Then 
> I add a bus free timeout counter and a message length timeout 
> counter. The Bus free timeout is for the condition mentioned above 
> and starts a timer when the start condition is requested and is 
reset 
> when the start condition has been transmitted. If too long a time 
> goes by without a start condition being sent, then the timeout 
would 
> reset the I2C interface so it no longer thinks the bus is busy. The 
> message length timeout also helps recover from the condition where 
a 
> master does not send out enough SCL clocks to complete a slave 
> transmission. If the slave send out a '0' and no more clocks are 
> received a "stuck bus" can occur. A message length timeout is 
started 
> when a start condition is received and reset when a stop condition 
is 
> received. If the stop condition is not received, the the I2C 
> interface is reset after a period of time and releases the bus from 
> it's "stuck" condition. These timeouts may vary depending on the 
> application.
> 
> Regards,
> 
> Jim E.
> 
> --- In lpc2000@yahoogroups.com, "semetex01" <info.semetex@s...> 
wrote:
> > 
> > --- In lpc2000@yahoogroups.com, "neptunus1000" <roykrikke@h...> 
> wrote:
> > > 
> > > Hello everybody,
> > > 
> > > is there realy nobody how had ths problem before. Or is there 
> realy 
> > > nobody how now's a solution.
> > > 
> > > Thanks Roy
> > > 
> > > --- In lpc2000@yahoogroups.com, "neptunus1000" <roykrikke@h...>
> > wrote:
> > > > 
> > > > Hello,
> > > > 
> > > > "Was there indeed a pull-up resistor missing on the Olimex
> > board?" 
> > > > YES there was one missing.
> > > > 
> > > > I put for the testing two pull-up on the bus of 4,7K and
> > connected 
> > > to 
> > > > the 3.3 Volt. When I'm debugging the program. The program is
> > still 
> > > > hanging on the while(I2STAT != 0x08);. When I measure the both
> > I2C 
> > > > lines with pull-up, the lines have 3.3 Volt. The program is 
not 
> > > > working. If I disconnect the pull-up resistor the SDA line is 
> 3.3 
> > > > Volt and the SCL line is 0 Volt. This is oke if I look in the 
> > > schema 
> > > > of the Olimex board. I really don't understand why it is not 
> > > working.
> > > > 
> > > > Of course I can build some code for 'bit-bang', but if the uC 
> has
> > a 
> > > > I2C bus. Then it is ugly to build a 'bit-bang' routine.
> > > > 
> > > > I measured with a FLUKE 123 scope meter.
> > > > 
> > > > Best Regards
> > > > Roy
> > > > 
> > > > --- In lpc2000@yahoogroups.com, "Aalt Lokhorst" 
<lokhorst@s...> 
> > > wrote:
> > > > > Hello Roy,
> > > > > 
> > > > > Was there indeed a pull-up resistor missing on the Olimex 
> board?
> > > > > 
> > > > > If you can measure low and high levels on both I2C lines now
> > then 
> > > I 
> > > > > expect that the hardware is fine. If there is also a I2C 
> device 
> > > on 
> > > > the 
> > > > > bus and it is still not working then i assume it is a 
> software 
> > > > problem.
> > > > > 
> > > > > In the past I used I2C on a 8051 with some 'bit-bang' 
> routines. 
> > > > Until 
> > > > > now I didn't use the I2C of the ARM. This will change in the
> > next 
> > > > few 
> > > > > weeks but for the moment I can't help you.
> > > > > 
> > > > > In the files section of the yahoo group are some examples. 
If
> > the 
> > > > > pull-up indeed was missing in the hardware then you 
probably 
> > > spend 
> > > > a lot 
> > > > >   of time with software debugging without any change to 
> succeed.
> > > > > Might be the moment to start debugging again, use an
> > oscilloscope 
> > > > if you 
> > > > > have it and study the signals to see where it fails.
> > > > > 
> > > > > Best Regards
> > > > > Aalt,
> > > > > 
> > > > > 
> > > > > -- 
> > > > > ==============================
> > > > > Aalt Lokhorst
> > > > > Schut Geometrische Meettechniek bv
> > > > > Duinkerkenstraat 21
> > > > > 9723 BN Groningen
> > > > > P.O. Box 5225
> > > > > 9700 GE Groningen
> > > > > The Netherlands
> > > > > Tel: +31-50-5877877
> > > > > Fax: +31-50-5877899
> > > > > E-mail: Lokhorst@S...
> > > > > ==============================
> > > > > 
> > > > > 
> > > > > neptunus1000 wrote:
> > > > > > 
> > > > > > Hello Aalt,
> > > > > > 
> > > > > > with on both lines a pull-up the code is still not working
> > oke.
> > > > > > Please help my.
> > > > > > 
> > > > > > --- In lpc2000@yahoogroups.com, "Aalt Lokhorst"
> > <lokhorst@s...> 
> > > > wrote:
> > > > > >  > Hello Roy,
> > > > > >  >
> > > > > >  > Is there a pull-up on the SCL line? I can't find it in 
> the
> > > > > > schematic
> > > > > >  > drawing but probably I missed it.
> > > > > >  >
> > > > > >  > As far as I know both lines need a pull-up because SDA 
> and 
> > > SCL
> > > > > > lines are
> > > > > >  > 'open-drain' outputs.
> > > > > >  >
> > > > > >  > Best Regards,
> > > > > >  > Aalt
> > > > > >  >
> > > > > >  > --
> > > > > >  > ==============================
> > > > > >  > Aalt Lokhorst
> > > > > >  > Schut Geometrische Meettechniek bv
> > > > > >  > Duinkerkenstraat 21
> > > > > >  > 9723 BN Groningen
> > > > > >  > P.O. Box 5225
> > > > > >  > 9700 GE Groningen
> > > > > >  > The Netherlands
> > > > > >  > Tel: +31-50-5877877
> > > > > >  > Fax: +31-50-5877899
> > > > > >  > E-mail: Lokhorst@S...
> > > > > >  > ==============================
> > 
> > Roy,
> > 
> > I had this problem (I2C start not generated and I2C status at 0xf8
> > forever) on an Olimex board (LPC-WEB 2124) and a pull-up on SCL 
> fixed
> > it.
> > 
> > H.A.