Hello,
I have played with the cjmcu-2317 a few times, with always positive results.
Not having needed to use multiple boards I didn't look into addressing.
Today I need to use 2. Not finding anything specific to the cjmcu-2317 but more than enough about the dip package MCP23017 where it clearly states the address pins need to be pulled either high or low for the chip to function correctly and cannot be left floating.
Here comes my surprise.
My previous endeavors have never yielded the board being in the wrong address at power on.
Do any of you know,
-Does the cjmcu-2317 has internal pulldown resistors on the address pins? I see some- 103 resistor arrays and a couple of isolated ones on the board next to the smd package mcp23017.
EDIT: I checked the traced but the chip is siting on most of the endpoints , the soldermask is also black .. ( rolleyes ). I do seem to think A2 passes over the bottom right pin of the resistor array.. but can't be sure.
-Is, not having problems reason enough to assume they added a pulldown?
-Would you just pull 1 pin on 1 board high and keep on testing for the duration of the project? Or attach the other 7 pins to ground just to be safe and not bother with finding out?
I am curious tbh.
friendly regards