AXE033Y PICAXE 18M2 Interfacing

Hi, I know this thread has been started before but the others have no solutions that fix this for me.

Hooked up Serial OLED Display (AXE033Y with DS1307 clock upgrade) to PICAXE 18M2 High Power Project board

Originally used serial mode and connected the "in" and "out" of the AXE033Y to 2 pins of the PICAXE 18M2. All worked fine- could set time, alarms and all was good.

The display worked fine and displayed text as I wanted.

However I required 2 alarms so wanted to use i2c mode for the PICAXE to read the time continuously and check if the alarm time was reached while continuously displaying the time on the OLED.

I put a jumper across the mode connectors to change it to i2c and changed the serial leads to the SCL and SDA format (B.1 and B.4 on the PICAXE)

Loaded up the i2c test code (Hello!123) from the datasheet and waited for program to run. Nada.

The display was blank, i've checked continuity between pins on the master project board 18M2 and the slave OLED 18M2. Both boards are powered up 5V regulated.


The OLED board has the power connections shorted since the diode was causing a voltage drop when I ran it in serial mode and the time wasnt advancing.

Any suggestions?

Thanks all.

You have connected B.1 and B.4 directly (to the pads beside the PICAXE chip), not to the FET buffered outputs on right hand side?

This particular board is not ideal for this, as it also has pull down resistors on the FETs (e.g. on B.1) which will also need to be removed.

Technical said:

You have connected B.1 and B.4 directly (to the pads beside the PICAXE chip), not to the FET buffered outputs on right hand side?

This particular board is not ideal for this, as it also has pull down resistors on the FETs (e.g. on B.1) which will also need to be removed.

Click to expand...

Appreciate this, i've connected to the pads by the chip like you say. How can I modify the board to allow i2c to work? bend out the i2c pins from the picaxe 18 and solder directly to them?

Authentic said:

Appreciate this, i've connected to the pads by the chip like you say. How can I modify the board to allow i2c to work? bend out the i2c pins from the picaxe 18 and solder directly to them?

Click to expand...

Remove the pull down resistors from the FETs connected to the i2c pins. Bending the pins out might damage them and is something that should only be attempted with cheap logic ICs and only temporarily.

nick12ab said:

Remove the pull down resistors from the FETs connected to the i2c pins. Bending the pins out might damage them and is something that should only be attempted with cheap logic ICs and only temporarily.

Click to expand...

I can do that for one of the outputs but the other goes through the L293D motor driver chip,

If you remember the L293D chip from the socket B.4 should work ok. It is probably only the pull down on B.1 that is the issue to workaround physically.

Technical said:

If you remember the L293D chip from the socket B.4 should work ok. It is probably only the pull down on B.1 that is the issue to workaround physically.

Click to expand...

or remember to remove the L293D

As, from the CHI-035A datasheet the L293D is an option in the first place, are you using that chip for your project or not?

westaust55 said:

or remember to remove the L293D

As, from the CHI-035A datasheet the L293D is an option in the first place, are you using that chip for your project or not?

Click to expand...

Removed the pull down resistor array and still nothing. Tried with L293D installed and not installed.

Code: