Alan B. Pearce wrote :


> This [PCF8574] is really quite a nice chip to get an easy to use 8 bit
> port on an I2C bus. You can have up to 8 of the non-A
> version, and up to 8 of the -A version, giving the potential
> for 16 ports. The only difference between the two versions
> is the base address on the I2C bus.

Has anyone had the chance to compare with the Microchip
MCP23016 part ? With that you get :
- Two full 8-bit ports.
- True Input or output pins with 25mA source and sink as output.
- Programmable "inverter" for input bits.
- R/W "latch" regs, like the 18-series. You can read back what was
   written, not what's on the actual pins.
- Two "capture" regs that takes a "snapshot" of the inputs at the
   actual time of the interrupt.

And it's $2.66 in single quantity (BuyMicrochip-US) v.s $2.00
for the Philips part (single quant from Digikey), so less cost/pin.

Note that there is a rev.B data sheet for the MCP23016 since
sep-2003. The former A data sheet was "Preliminary"...

I've got the impression that the MC part is a bit less popular,
it's "non stock" at Digikey...

Jan-Erik.

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