Need help for reading I2C Sensor

Hello *

This is my first time i do somthing with I2C. I tray to read a digital pressure transducers from Sensor Technics. I use the CSDX Series.


the code is:

I2C_data var PORTB.1 ' I2C Daten Leitung
I2C_clock var PORTA.4 ' I2C Clock Leitung



Main:


I2CRead I2C_data,I2C_clock,$F1,0,druck,druck2 ' Read string from slave
Pause 10

lcdout $FE,$D4,"Druck ",dec druck, "mbar" ,dec druck2'

pause 10

goto main


on the display nothing is changing.


Thanks for your help.


Rolf





The Data Sheet is under :

http://www.sensortechnics.com/index....91f3ec91b908bd

Try this!!
I2CRead I2C_data,I2C_clock,$F1,0,[druck,druck2]
Manual page 82-85
And I hope you did'n forget the pullup resistors for the i2c lines

Or even if the circuit is operating or not in the first place...heartbeat LED...

I will tray out the new code on Monday. Can you tell me for what is the [ ] ?
The Pull Up resistors are on the board.

Thanks

Quote:

---

Originally Posted by Omalik

I will tray out the new code on Monday. Can you tell me for what is the [ ] ?

---

It's in the manual...

Here is an example of how I use I2C with an EEPROM and the I/O Expander, I hope it helps.

<code>

DEFINE I2C_HOLD 1

Address VAR WORD
SCL VAR PORTC.3 ' I2C Clock pin
SDA VAR PORTC.4 ' I2C Data pin

Address = 0



'------------------------------------------------------------------------------------------------
' Read Password from EEPROM
'------------------------------------------------------------------------------------------------
ReadPassword:
Address = 0
I2CREAD SDA,SCL,$A0,Address,[Password[1],Password[2],Password[3],Password[4]]
Return
'------------------------------------------------------------------------------------------------



'------------------------------------------------------------------------------------------------
' Save Password to EEPROM
'------------------------------------------------------------------------------------------------
SavePassword:
Address = 0
I2CWRITE SDA,SCL,$A0,Address,[Password[1],Password[2],Password[3],Password[4]]
Return
'------------------------------------------------------------------------------------------------



'------------------------------------------------------------------------------------------------
' Subroutine to handle I2C errors
'------------------------------------------------------------------------------------------------
I2CError:
LCDOut $fe,1
LCDOut $fe,2, "I2C Bus Timed Out" ' I2C command timed out
Pause 1000

GoTo loop
'------------------------------------------------------------------------------------------------



'------------------------------------------------------------------------------------------------
' Setup I2C I/O Expander
'------------------------------------------------------------------------------------------------
SetupIOExpander:
'*** Setup I/O Expander PortA as Output, PortB as Input ***
I2CWrite SDA,SCL,$40,[6,0,31], I2CError
Pause 150

'*** Set the Interrupt Capture Rate to Fast ***
'I2CWrite SDA,SCL,$40,[11,1], I2CError
'Pause 150

'*** Set I/O Expander PortA Outputs to LOW ***
I2CWrite SDA,SCL,$40,[0,0], I2CError
Pause 150

RESUME
'------------------------------------------------------------------------------------------------

</code>

I tray out

I2CRead I2C_data,I2C_clock,$F1,0,[druck,druck2]

but it does not work at all. I find a lot of examples for Eeprom but not one for the sensor I use.

does some have any idea ?

Thanks

Quote:

---

Originally Posted by Omalik

I tray out

I2CRead I2C_data,I2C_clock,$F1,0,[druck,druck2]

but it does not work at all. I find a lot of examples for Eeprom but not one for the sensor I use.

does some have any idea ?

Thanks

---

From what I can see in the data sheet you should be using this:

I2CRead I2C_data,I2C_clock,$F1,[druck,druck2]

I don't know what the 0 you had there was for but the R/W bit is set by the I2CRead/I2CWrite command, you don't need to set it.

also check what you have druck and druck2 declared as, byte or word.

Quote:

---

Originally Posted by PJALM

From what I can see in the data sheet you should be using this:
I2CRead I2C_data,I2C_clock,$F1,[druck,druck2]
I don't know what the 0 you had there was for but the R/W bit is set by the I2CRead/I2CWrite command, you don't need to set it.

---

Probably should be using $F0 instead of $F1 also.

i did a picture on the KO.
blue is clock and red are data.

and i can not read the sensor.

Quote:

---

Originally Posted by skimask

Probably should be using $F0 instead of $F1 also.

---

see datasheet

Quote:

---

Originally Posted by Omalik

see datasheet

---

Right...and PBP handles the R/W bit for you...as stated a few posts above.

Now the sensor is working well

Thanks for all your help

The code I use is:



I2CRead I2C_data,I2C_clock,$F1,[druck]

an to calculate the mbar:

IF druck > 1999 then ' nur positive Druck auswerten

druck = ((druck - 2000) * 6) + ((druck - 2000) /4) ' * 25 / 100

else
druck = 0

endif
see also the printscreen from the I2C bus.

I am glad to see that you got it working :)