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In lugnet.robotics.nxt, Christian Mock wrote:
> In lugnet.robotics.nxt, Ralph Hempel wrote:
> > Christian Mock wrote:
> > > Hi,
> > > has anybody successfully tried to read ports from I2C connected PCF8574 with
> > > pbLua (Beta-8) ?
> > > Writing and setting ports is no problem, but reading ports fails. The return
> > > value is every times 0 (not NIL)
> >
> > No ideas yet, Christian. I do have a Mindsensors kit here to look
> > at over the weekend. Are you SURE you are sending the correct string
> > to read the registers?
> >
> > Can you post the code you're using for the test here?
> >
> > Cheers, Ralph
>
> Hi Ralph,
>
> we are using this code:
>
> collectgarbage( "setpause", 110 );
> function setupI2C(port)
> nxt.InputSetType(port,2)
> nxt.InputSetDir(port,1,1)
> nxt.InputSetState(port,1,1)
> nxt.I2CTimer(3)
> nxt.I2CInitPins(port)
> end
>
> function ReadPCF(port)
> nxt.I2CSendData( port, string.char(0x73),1, 1 )
> while( 0 ~= nxt.I2CGetStatus(port)) do
> end
> s = nxt.I2CRecvData( port, 1 )
> print( "Daten " .. s )
> end
>
> setupI2C(4)
> ReadPCF(4);
>
> Do you think, we have to read I2C address more often ? Like ultrasonic sensor ?
> The first read result of ultrasonic is allways 0.
>
> Thanks for more :D
> Bye
> Christian
>
>
> ---
Hi,
we solved the problem... Lego-Firmware has own brain and handle read/write
with own mechanisms ;-( The last read/write bit is handled automatically by
lowlevel routines.
Reading the same address like writing solves the problem.
collectgarbage( "setpause", 110 );
function setupI2C(port)
nxt.InputSetType(port,2)
nxt.InputSetDir(port,1,1)
nxt.InputSetState(port,1,1)
nxt.I2CTimer(3)
nxt.I2CInitPins(port)
end
function ReadPCF(port)
nxt.I2CSendData( port, string.char(118),1, 1 ) -- hier wird Geschrieben um zu
Lesen
while( 0 ~= nxt.I2CGetStatus(port)) do
end
s = nxt.I2CRecvData( port, 1 )
print( "Daten " . s )
c1 = string.byte(s,1,1)
print( string.format( "Result: %3i", c1 ) )
end
---
setupI2C(4);
ReadPCF(4);
Hmmm, why this ?
Bye
Christian
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Message has 1 Reply:
Message is in Reply To:
 | | Re: pbLua PCF8574
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| (...) Hi Ralph, we are using this code: collectgarbage( "setpause", 110 ); function setupI2C(port) nxt.InputSetType(port,2) nxt.InputSetDir(port,1,1) nxt.InputSetState(port,1,1) nxt.I2CTimer(3) nxt.I2CInitPins(port) end function ReadPCF(port) (...) (19 years ago, 19-May-07, to lugnet.robotics.nxt, lugnet.robotics.nxt.nxthacking)
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