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gadam
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Posts: 7
Joined: Wed Aug 11, 2021 4:58 pm

Issue with KNOT GPIO Digital Input

Wed Aug 18, 2021 5:54 pm

Hi All,

I have asked the below already in "KNOT and GPIO" with no comments so far and I have opened Support ticket with no response yet either.

I seem to have some issue with the KNOT GPIO, I hope someone might help. I'm not sure if the there is a bug in the ROS, faulty board or the docummented thresholds of the Digital Input (Digital input voltage is 0-2.5 V max. To receive a logical "0" on the pin, the voltage should be between 0-0.3 V. To receive a logical "1" on the pin, the voltage should be between 0.7-2.5 V.) but it seems the Input does not react to the voltage. I have single cell battery connected between pin1 (negative) and pins 2, 3, 5 (positive), the analog pins read the voltage, the digital is always 0. I have tried the testing and stable branch - stable does not read analog, please see below:
===

# jan/02/1970 01:33:07 by RouterOS 6.49beta54
#
# model = RB924i-2nD-BT5&BG77

[admin@MikroTik] /iot gpio> analog print
 # NAME                                                        VALUE       OFFSET
 0 pin2                                                       1215mV          0mV
 1 pin3                                                       1264mV          0mV
[admin@MikroTik] /iot gpio> digital print
Flags: X - disabled 
 #   NAME                      DIRECTION OUTPUT INPUT SCRIPT                     
 0   pin5                      input     0      0    
 1   pin4                      output    0     
 2   pin6                      output    0     
[admin@MikroTik] /iot gpio> 

===

# jan/02/1970 01:47:32 by RouterOS 6.48.3
#
# model = RB924i-2nD-BT5&BG77

[admin@MikroTik] /system gpio> print
Flags: X - disabled 
 #   NAME                      DIRECTION OUTPUT INPUT SCRIPT                     
 0   pin5                      input     0      0    
 1   pin4                      output    0     
 2   pin6                      output    0     
[admin@MikroTik] /system gpio> 

===
Any idea?

Kind regards,
Adam
 
gadam
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Topic Author
Posts: 7
Joined: Wed Aug 11, 2021 4:58 pm

Re: Issue with KNOT GPIO Digital Input

Tue Aug 31, 2021 4:10 pm

Just in case someone else would be stuck with the digital input not working, there is update from Mikrotik:

"We have retested and revised the manual regarding the RB924i-2nD GPIO specs:

note: Digital input voltage is 0-2.5 V max.

Without PCB pull-up resistor:

to receive a logical "0" on the pin, the voltage should be between 0-1.47 V;
to receive a logical "1" on the pin, the voltage should be between 1.48-2.5 V.
With PCB pull-up resistor:

to receive a logical "0" on the pin, the voltage should be between 0-1.34 V;
to receive a logical "1" on the pin, the voltage should be between 1.35-2.5 V."

I have not yet tested it but sounds very promising.

Kind regards,
Adam

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