In SX Microcontrollers, SX/B Compiler and SX-Key Tool, verobel wrote:

Fellow sx/b coders;

I am trying to learn SX/B and have run some examples by others successfully but..
I wired up a 2 digit 7 seg. lcd on the PDBoard and initially got it to count from 0 to 99 in a loop.
Next I added 2 I2C chips DS1621 (no examples available) and 24LC64 (some examples available).
In the current program TempDI2.SXB I am trying to display the temperature but get -5  when I expect ~22

The new code (added to the previously working program) is shown below. The full program listing is attached.

 

Main:
  DO
      tempC = GET_TEMP
      tens = tempC / 10
      ones = tempC // 10
  ...

 

' Subroutine Code
' -------------------------------------------------------------------------
' GET_TEMP
' gets temp from DS1621 using I2C commands
' USE: temp = GET_TEMP
 GET_TEMP:    
 
  I2CSTART SDA 
  I2CSEND SDA, addrW                          ' prepare for convert command
  I2CSEND SDA, cmdConv    ' request convert 1 temp. sample
  I2CSEND SDA, addrR    ' prepare for readTemp command
  I2CRECV SDA, tempIn_MSB, Ack   ' read the 2 bytes
  I2CRECV SDA, tempIn_LSB, Nak
  I2CSTOP SDA
  RETURN tempIn_MSB    ' ignore 1/2 deg LSB for now

 Could some one confirm if the I2C sequence of commands is good.
 Could some one spot any obvious error in my SX/B code that would explain the wrong output -5 on the display?

 

 I believe the wiring is good: have Ra.0=SDA 1621.1, Ra.1=SCL 1621.2 both with 4.7k pullup resistors.

A0=1 (5V), A1=0,A2=0
Thanks, John

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