[SOLVED] some GPIO pins do not produce any output.
Hello,
I have made a shield for an Up squared and started testing it, but ran into problems with configuring some pins as outputs.
I have a UP² with N4200, 4GB RAM and 32GB eMMC, run Linux (had a flavor of Debian, but put now Ubuntu 18.04 on it), and have BIOS 3.3 on it.
I am able to set some pins as outputs (e.g. 16 and 18 (linux pins 471 and 405)) and steer a led with it. For this I used the example of the UP2 pinout page: https://wiki.up-community.org/Pinout_UP2. However some I can configure as output, but the pin output does not change.
Thinking it might be my shield, I repeated the test with another board, the UP² with E3940, 4GB and 32GB eMMC, on which I never put a shield, but I still have problems in setting outputs (in my case pin 13 and 15 (432 & 431).
I tested all pins and came with the following result:
Physical pins of which I can set the output and work perfect: 8, 11, 12, 16, 18, 22, 23, 24, 26, 29, 32, 33, 40 (Linux gpio 477, 478, 326, 471, 405, 402, 419, 420, 430, 468, 469, 329)
Physical pins of which I cannot toggle the output (but I do not get any error, while setting it up): 7, 10(UART_RX), 13, 15, 31, 37, 38(AVS_I2S6_SDI) (Linux gpio 433,476, 432, 431, 404, 403, 328)
Physical pins that are always 3V3: 3, 5, 27, 28 (all I2C) (Linux gpio 462, 463, 464, 465)
Physical pins that are always 0V: 19 (SPI MOSI) (linux gpio 422)
I can understand that some pins maybe cannot work because of their function (I2C, UART_RX), but some pins that are only gpio, should work as output, right?
I already searched the community and couldn’t find anything.
Since the problem occurs on multiple pins, there might be a very simple cause (and hopefully very simple solution).
I hope you can help me!
Kind regards,
Henk
Comments
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Hi @Henk ,
I would recommend you to install the UP kernel for Ubuntu 16.04.
Ubuntu 18 is still not supported for UP community.
Please, check the easy steps and try again to test only the GPIO pins, first:
https://wiki.up-community.org/Ubuntu
Thank you!
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That solves it all! It works now as expected.
Thanks for the quick reply!Would it be an idea to add this also to the pin-out page as remark? Since Linux-out-of-the-box does supports the majority of the pins, people (like me
) do not look further...
Although we right now also have this thread.
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