Thank you for your efforts Neil.
I THINK there is a typo in the PCF8574 section (top of page 129 in Dec edition)...
According to the 7 bit address table shown - 0 0 1 0 A2 A1 A0 , shouldn't the addresses for the PCF8574 in the following table start at 0x10?
The PCF8574A entries look right - both tables agree, its just the (non-A) part that looks wrong to me
Again, great work
Regards
Les Otter UK