Comments on: GPIO on ALIX.3D3

By: Ricardo

Ricardo — Thu, 26 May 2011 15:49:51 +0000

@twam
thanks for the prompt answer
So I have no idea what to do now with this, as unfortunately the included Geode doesn’t even support the serial port handshake signals (for the PPS people often use the DCD signal). If you have any suggestion (other than polling some port), it would be really welcome!

Thanks
Ricardo

By: twam

twam — Thu, 26 May 2011 15:44:55 +0000

@Ricardo As far as I know it is not possible to use them as a real interrupt source.

By: Ricardo

Ricardo — Thu, 26 May 2011 15:23:35 +0000

@twam

Hi!
I’ve been working with the Alix.3d3 for a while now but only lately I had the need to use external interrupts.
I can understand that by polling one of the GPIO pins frequently enough, it could “almost” work as an interrupt. However, in my case, a “real” interrupt is necessary because I’m trying to connect a GPS PPS signal to this board (which in turn gives me precision for message time-stamping purposes). Do you know of any way to use the already “visible” pins on this board and make them interrupt inputs?

Thanks a lot
Ricardo

By: l

Tue, 21 Dec 2010 14:59:12 +0000

hi.
can you please provide step-by-step tutorials on how to compile the kernel? i am having errors. please help.

By: Marco

Marco — Mon, 27 Sep 2010 11:13:50 +0000

Ok, thanks for your help.
I try this solution.

Thank you.
Best regards,Marco

By: twam

twam — Mon, 27 Sep 2010 11:04:34 +0000

@Marco The switch is connected to a GPIO pin. So you can use it as long as your are polling it frequently enough.

By: Marco

Marco — Mon, 27 Sep 2010 11:00:45 +0000

Ok.thanks.
But Can I use the signal on the switch for status change…?
Or isn’t there a possible solution…?

thanks.

Marco

By: twam

twam — Mon, 27 Sep 2010 10:45:44 +0000

@Marco As far as I know, there is no support for pin change notifications in the GPIO interface yet. So your programm would need to poll the pin very often and your signal must be long enough.

By: Marco

Marco — Mon, 27 Sep 2010 10:37:22 +0000

Hi twam, thanks for your tutorial. It’s very best…:)
But I have a question, in fact I have a problem. I built a power supply from use as battery, this system send a
electric signal on CTS pin of the COM1, but this PIN is not enabled on CS5536 (alix6e2), I read this on the manual.
I had an idea reading your tutorial, but I need help.
Can I send a electric signal on the switch, and can I read the change status…???
Also what would be the ideal power of the electrical signal…???

Can you help me, please…???

Thanks.

Marco

By: Bula

Bula — Fri, 17 Sep 2010 13:51:50 +0000

OK thanks, it is what I was thinking but I was not sure cause of difference in buffer types between modeswitch and leds GPIO ports. Only thing I need now is external 3V

By: twam

twam — Fri, 17 Sep 2010 13:15:49 +0000

@Bula here you can find the schematic of the ALIX.3D3. You should connect the LED to same way as the other 3 LEDs.

By: Bula

Bula — Fri, 17 Sep 2010 13:13:00 +0000

For now I need only one LED so – do you mean to connect diode thru pull-up resistor on external 3V or directly on 3.3V that I get on the modeswitch pins?

By: twam

twam — Fri, 17 Sep 2010 11:10:49 +0000

@Bula I think you could use the modeswitch GPIO Port for an LED if you connect to thru a resistor to 3V. But I would recommend to use an I²C Port Extender if you need more GPIO Pins.

By: Bula

Bula — Fri, 17 Sep 2010 11:04:06 +0000

Hi twam, thank you for your help. Leds trough gpio are working ok but I have questions about modeswitch: is it safe to use it as output for another led? I see that its buffer type is smb and not gp24 as the ones for leds?

By: twam

twam — Wed, 09 Jun 2010 16:05:19 +0000

@Yago Fernandez Hansen I never used the old device module as I is not compatible with the GPIO interface of the kernel. Also this will be removed in future kernel version, so it is better not to use it in new projects.

By: Yago Fernandez Hansen

Yago Fernandez Hansen — Wed, 09 Jun 2010 14:26:48 +0000

Dear twam:

Thank you for your wonderfull articles about alix.3d3 board. I am working in a project in Voyage Linux for this board, and I am very pleased of how everything works with release 0.6.5. Very small bugs with a very good functionallity. I have readed your articles about LEDS, GPIO, etc… and they helped much. The problem I have, as I readed in one of your articles is that I want to use the gpio24 for a switch and I have asked about it and If I don’t want to compile the kernell (I hate that) I can now use and load with modprobe the cs5535 as this:

voyage:~# modprobe cs5535_gpio

voyage:~# dmesg | grep gpio
[ 14.847516] cs5535_gpio: base=0×6100 mask=0xb003c66 major=253

voyage:~# lsmod | grep gpio
cs5535_gpio 3744 0

voyage:~# ls -l /dev/cs5535*
crw-rw—- 1 root root 253, 1 Jun 6 21:37 /dev/cs5535_gpio1
crw-rw—- 1 root root 253, 10 Jun 6 21:37 /dev/cs5535_gpio10
crw-rw—- 1 root root 253, 11 Jun 6 21:37 /dev/cs5535_gpio11
crw-rw—- 1 root root 253, 12 Jun 6 21:37 /dev/cs5535_gpio12
crw-rw—- 1 root root 253, 13 Jun 6 21:37 /dev/cs5535_gpio13
crw-rw—- 1 root root 253, 2 Jun 6 21:37 /dev/cs5535_gpio2
crw-rw—- 1 root root 253, 24 Jun 6 21:37 /dev/cs5535_gpio24
crw-rw—- 1 root root 253, 25 Jun 6 21:37 /dev/cs5535_gpio25
crw-rw—- 1 root root 253, 27 Jun 6 21:37 /dev/cs5535_gpio27
crw-rw—- 1 root root 253, 5 Jun 6 21:37 /dev/cs5535_gpio5
crw-rw—- 1 root root 253, 6 Jun 6 21:37 /dev/cs5535_gpio6

And it’s very easy and is ok. But just a stupid question. How can I read when I want or as is changed the value of the switch: 0/1? Can you help me?

Thank you

Yago

By: twam

twam — Fri, 18 Dec 2009 07:23:54 +0000

The cs5535-gpio support via the GPIO interface is in kernel mainline since version 2.6.33-rc1. Commits are 5f0a96b044d8edaee20f4a32ef6c393599ca55f8 and 1ea3fa7bbfbe81cfbdcc35748a57c35f9b32c5d6.