Hello PIC.ers,

I've been a longtime lurker, only an occasional contributor.

I have an app. that has been in production now for ~7years using 
various PICs. Started with the 16F877, then 18F452 and I am being
`encouraged' to migrate to the modern 18F4520.

Differences seem minor enough, but the one that is sticking me right now
is the MSSP in master mode.
The I2C bus has  3x 8bit expander IO ports (PCF8574s) hanging off it
and a DS1307 RTC.
So far, only one of the IO port expanders takes messages from the master,
the others seem unreadable.

I haven't (yet) gone the whole hog of stripping down all the source code
to essentials so that the exact problem can be drilled into.

Does anyone out there know of any gotchas or pointers in this migration?



        bestos,  John

eMail from the desk of John Sanderson.
JS Controls cc. Manufacturer and purveyor of Force testing
apparatus.
john@jscontrols.co.za
www.jscontrols.co.za
Tel: +27 (0) 11 975 1730
Fax: +27 (0) 86 516 9725
Cell: +27 (0) 82 741 6275
PO Box 1887, Boksburg 1460,
Rep. of South Africa
VAT 4280246036
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