MCP23017 device address pins switchable

[tito-t]

hello,
so far I was using 1 MCP23017 with all address pins connected to GND which worked fine.
Now I want to join a 2nd and perhaps a 3rd one to the bus, and for that purpose I want to make the device address pins switchable by jumper switches.
I'm not quite sure but I assume that one could make it that way:

- default: addr pin connected to 10kOhm, then to GND (== pulldown resistor)
- switchable to + 3.3V optional (strong pullup, no resistor)

acc. to this chart:

MCP23017_addr_jumper.jpeg (10.79 KiB) Viewed 1343 times

would it be correct that way?

[DougieLawson]

Follow this schematic
http://quick2wire.com/wp-content/upload ... 7-v0-5.pdf

[tito-t]

thank you!
Unfortunately I can't recognize it clearly -
10k pulldown to GND is like I assumed,
then each switch via a capacitor (size=?) to GND
-
but what is the medium pin for a pullup? It's strangely between 3.3V and 5V, but what is it actually? If it's also 3.3V then it would also match my chart.

[DougieLawson]

It depends whether you're running the MCP23017 at 3V3 or 5V0.

[tito-t]

ok,fine, so straight to +Vc

Are you able to read he capacitor size beyond the switches to GND?

[DougieLawson]

That's a 0.1uF ceramic capacitor.

[tito-t]

excellent, thank you very much!