All Questions
4 questions
0
votes
0
answers
63
views
Does my GPIO Expander have a floating pin? [Button and pull-up resistor]
I am using GPIO expanders (MCP23017) for an array of buttons. Each button is connected between GND and an input pin of the expander. I've enabled the 100k internal pull-up resistor on the MCP23017 (...
1
vote
1
answer
74
views
Confused by i/o expander datasheet note re internal pull-ups
The inputs on the NXP PCAL6524 i/o expander can be configured with internal pull-up or pull-down resistors.
The datasheet states, "External resistors are required for inputs... that may float. If ...
- 11
1
vote
1
answer
226
views
Pull up/down a pin on a PCA9536 does not register?
Quite a obscure question here, concerning a very specific I2C expander IC, however I believe that this example can be replicated with most expander bus ICs.
I am using a PCA9536 to switch the 4 pins ...
- 13
1
vote
1
answer
8k
views
Are pull-up resistors needed when connecting buttons to a IO expander?
I'm connecting many momentary switches to a IO expander, like the MCP23017:
.
I read that I need to put pull-up resistors for each switch connected to the MCP23017. On another place (datasheet), I ...
- 2,178