pull_up_down in Matlab

Hi,

About the GPIO in raspberry pi - I need to enable the internal pull up resistor to read a 'high' value at the pin by default.

I see that in python you have the following command: GPIO.setup(PIN, GPIO.IN, pull_up_down=GPIO.PUD_UP)

Is there something similar in Matlab?

Answer 1

[Christopher McCausland]

Hi Sapir,

In MATLAB there is a "configurePin" command which can enable the pull up resistor. Here is the link to the documentation.

In short it looks something link this;

a = arduino('COM4','Uno');  %Link to the arduino 
configurePin(a,'D3','pullup'); % Configure the internal pull up on pin D3

Let me know if this helps you,

Christopher

[Sapir Zurist]

Hi Christopher,

this command and documentation relates to Arduino. I need for Raspberry Pi...

See the error that it gives me when I tried this command:

>> configurePin(rob, 18,'pullup');

Expected input to match one of these values:

'Unset', 'DigitalInput', 'DigitalOutput', 'PWM'

The input, 'pullup', did not match any of the valid values.

[Sapir Zurist]

I enable the pull up resistor through Python on the Raspberry itself and it works.

[Christopher McCausland]

Hi Sapir,

My appologies, I clearly wasn't paying as much attention as I should have been.

I am not sure if this is avaliable as a command though it should be. However with some hardware tinkering we should be able to make this happen;

1. When an RP boots the first eight GPIO's have pull-ups enabled and the rest have pull-downs enabled, you should be able to use this to your advantage.
2. Add in additional resistors to the circuit in place of the internal pull ups

Both of these solotions are not ideal however should allow you to continue with your work in the mean time. I cannot think of why MATLAB wouldn't allow this functionality however looking at this forum and others many the same problem can be found as far back as 2017 with the documentation of 'mode' suggesting it isn't currently possiable.