Converting code to arduino

Robotics and electronics discussion Software and microcontrollers
1

I have this code that is for a picaxe and I would like to convert it to arduino c code. I have very little knowledge of the wire library so I need any help you guys can provide.
Here is the picaxe code

#picaxe 20x2
#no_table
' PICAXE-20X2 sample program for Lego NXT Sensors
' **** AXE216 i2c Experimenter Board Setup ****
' J1 External Power Fitted (4.5V)
' J2 SCL Pullup  Not fitted (pullup is in sensor)
' J3 SDA Pullup  Not fitted (pullup is in sensor)
' H2 9V Power  Fitted (9V)
' Lego Ultrasonic Sensor (part 9846)
' Note this sensor is much more difficult than the other
' Lego sensors to use. Consider using the SRF005 instead!
' You must provide both 9V and 5V supplies .
' Also i2c needs to be hacked due to a bug in the ultrasonic i2c firmware
' This means only the ultrasonic sensor can be used at once on the i2c bus
' as we are now using a non-standard i2c protocol
' We recommnd using the SRF005 instead!

symbol distance = b0 'distance in cm
' Wires on NXT jack plug.
' Wire colours may vary. Pin 1 is always end nearest latch.
' 1 White +9V
' 2 Black 0V
' 3 Red 0V
' 4 Green +5V
' 5 Yellow SCL
' 6 Blue SDA
' Do not use i2c pullup resistor - already provided within sensor.

init:

'Slave address is $02
hi2csetup i2cmaster, $02, i2cslow, i2cbyte
hi2cout $41,($02)  'continuous mode
pause 100
main:

; read values
; This single line should work:
;hi2cin $42,(distance)
; but does not as dodgy firmware in ultrasonic sensor

; therefore here is the workaround

hi2cout ($42)  ; address $42
low B.7   ; fake an extra pulse
input B.7   ; back to input
hi2cin  (distance) ; read distance


; debug display
debug
; wait 1 second then loop
pause 1000
goto main

and here is what I have for arduino code which does not work(Nothing comes out of the serial port)

#include <Wire.h>

void setup()
{
  Serial.begin(9600);
  Wire.begin();
   Wire.beginTransmission(0x41);
}

void loop()
{

   
  Wire.send(0x42);             

  digitalWrite(19,LOW);
  pinMode(19,INPUT);

    char c = Wire.receive();
    Serial.print(c);         
  delay(1000);
}

Thanks for the help.

2

Hello.

What pins on the Arduino are you expecting the I2C to use? When you say “serial port” it sounds like you are referring to the TX and RX pins; the I2C module on the AVR is on the pins the Arduino labels as Analog 4 and 5.

- Ryan

3

I have it outputting the i2c data over serial and nothing comes out in the terminal.

4

Sorry, I didn’t understand you were talking about the serial monitor. Do you have some datasheet or website that explains this “non-standard” I2C protocol better?

It looks like you aren’t getting the slave address into your Arduino code. Maybe something like this would work better:

 Wire.beginTransmission(0x02);
 Wire.send(0x41);
 Wire.endTransmission();
...

Wire.beginTransmission(0x02);
 Wire.send(0x42);
...
 Wire.endTransmission();

Do you have a logic analyzer that you can use to look at what your PIC is doing and what your Arduino are doing?

- Ryan

5

It’s kind of complicated. The part does not have a data sheet it is part of a toy. I don’t actually have a pic so I thought I could convert it to my arduino to use the sensor.
Here is the post were that code is from : picaxeforum.co.uk/showthread … hlight=nxt.
So what your saying is my code should look like this

#include <Wire.h>

    void setup()
    {
      Serial.begin(9600);
      Wire.begin();
     Wire.beginTransmission(0x02);
Wire.send(0x41);
Wire.endTransmission();
    }

    void loop()
    {

       
 
Wire.beginTransmission(0x02);
Wire.send(0x42);

      digitalWrite(19,LOW);
      pinMode(19,INPUT);
Wire.endTransmission();

        char c = Wire.receive();
        Serial.print(c);         
      delay(1000);
    }
6

I tried the above code using int c instead of char c and got all 0’s displayed.