Can anyone tell me how to read the SAA1064 7-segment values?

[Mosolee]

Hi, I have a central heating system that displays it's info and error codes on 4 7-segment displays. These displays are driven by a SAA1064, like so:

This SAA1064 (the one I use) receives it's information through I2C from the main computer, and the displays are multiplexed.

Here's my problem: I have a raspberry pi (whose I2C bus is already in use, at 100KHz) and I want to use it to read the values being displayed. I would prefer not using an extra microcontroller just to parse what's being displayed or to sniff the I2C bus inside the central heating system (as I have little-to-no-experience in programming those). Would using I2C IO expanders be an idea? If so, how would this be wired?

 

[Ian]

Hi Mosolee, welcome to the forums .

This is perhaps a question more suited to our companion Electronics forum (www.electronicspoint.com), as it's a little specific for our DIY forum.