Old CBUS serial protocol specification-Any info out here?

[djsb]

I'm trying to understand the Old CBUS serial protocol as used in the PCE2111 64 segment duplex LCD driver,SAA1057 PLL synthesizer and SAA1061 port expander (datasheets attached). According to section 10.1.3 page 18 of the i2c_spec.pdf file attached, the CBUS is similar to the I2C protocol which it predates. I'm beginning to learn to use my Logic16 logic analyser, so I'm starting with the PCE2111 first.Has anyone used this bus or know where I may be able to find the specification? Thanks.

[Uunoctium]

long time ago i looked up for some information about c-bus, because an (now outdated) HVAC Contoller by Honywell, MCR200 used it to combine with additional others and connect them to their building-control software, called excel.
Most of information about was distributed by Clipsal, inventor of c-bus. Nowadays all of them are wiped, after Schneider aquired Clipsal. Maybe there is a little chance to recover them by archive.org
Found only an manual to setup an c-bus home-automation interface running in an docker container.
Inside are some -dead!- links to original Clipsal documents

https://buildmedia.readthedocs.org/media/pdf/cbus/latest/cbus.pdf

[djsb]

Thanks Uunoctium for your reply.
That's a different thing altogether. C-BUS is for home automation (that's all I know about it-I don't have a home I can automate, so I'm not interested in it). The protocol I'm referring to is an inter integrated circuit communication serial protocol that was used before I2C was invented.
I've got ALL the segments on the LCD lit up so far, so I've got the beginnings of a driver(with some help from the CCS C forum).
I'll update this topic later as I make further progress. Thanks.

[djsb]

Here are the Revox B261 uP control block diagram, the uP controller schematic (which has a SAA1061-3 port expander) and the keyboard schematic which has a SAA1061-2 chip and a CD4532 priority encoder chip. I'm assuming that the -3 and -2 after the chip part number referes to the address that can be hard wired using pins 4 and/or 7 by connecting to VDD or ground as required. I am not sure how SAA1061 is addressed in the serial data stream or how the port direction is set? Can anyone help? Thanks.





PS. SAA1061 datasheet is in the first post to this topic. Thanks.