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.