Input buffers that generate interrupts on changes

[Chris Caudle]

> any important transitions.  I am looking for suggestions for chips
> that would not only allow reading the state of inputs in that way but
> would also provide a way to trigger a Coldfire interrupt on any
> transition.

I don't know of any parallel buffers which provide that, but I2C I/O
expanders can have that option.  The NXP (formerly Philips) PCF8574 and
PCF8575 have that feature, and Microchip sell a pre-programmed micro that
acts like an I2C expander as MCP23016.
If you want to keep the current parallel access device, you could always
hang a cheap PIC off the lines in parallel, which did nothing but loop
through reading the bits, and generating an interrupt on change.  Should
only add about $0.50 to $1 extra, and the program should be about a dozen
lines.

-- 
Chris Caudle