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 Robotics / NXT / NXT Firmware Hacking / 54
53  |  55
Subject: 
Re: pbLua PCF8574
Newsgroups: 
lugnet.robotics.nxt, lugnet.robotics.nxt.nxthacking
Date: 
Sat, 19 May 2007 18:40:40 GMT
Viewed: 
144 times
  
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


---



Message has 1 Reply:
  Re: pbLua PCF8574 SOLVED
 
(...) 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. (...) (18 years ago, 21-May-07, to lugnet.robotics.nxt, lugnet.robotics.nxt.nxthacking)

Message is in Reply To:
  Re: pbLua PCF8574
 
(...) 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 (18 years ago, 19-May-07, to lugnet.robotics.nxt, lugnet.robotics.nxt.nxthacking)

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