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Accessing hardware on the Edison?

Workshopshed

I'm wondering about accessing the GPIO of the Edison in high-level languages such as Python or Node.

 

So far I've found MRAA but wondered if there are other options?

 

https://github.com/intel-iot-devkit/mraa

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  • MRAA should be the way to go.  Looks like they have Python interface.

     

    Check out this link:

    Getting Started With Intel Edison - Python Programming - All

     

    I cannot wait to play with Python and Node on the Edison. Plans are to make that an early write up.

     

    I was wondering if Firmata would work or how does the Arduino and Atom systems communicate?

  • in reply to jasonwier92

    This article suggests you'd need to be root to run things that access MRAA

     

    https://communities.intel.com/thread/60492

  • in reply to Workshopshed

    There's an article here that is worth reading (the second part) if you want to detect pin changes.

    https://www.linux.com/learn/intro-to-Linux/2017/3/intel-edison-linux-maker-machine-matchbox

     

    Mark

  • in reply to mcb1

    So a little more playing

     

    It seems that under /usr/bin there is mraa-gpio which is happy to run from the command line.

    The options are.

    root@edison:/usr/bin# mraa-gpio
Invalid command, options are:
list              List pins
set pin level     Set pin to level (0/1)
setraw pin level  Set pin to level (0/1) via mmap (if available)
get pin           Get pin level
getraw pin        Get pin level via mmap (if available)
monitor pin       Monitor pin level changes
version           Get mraa version and board name
root@edison:/usr/bin#

     

    mraa-gpio version gives you

    Version v1.0.0 on Intel Edison

     

    while list

    root@edison:/usr/bin# mraa-gpio list

    00       J17-1: GPIO PWM
01       J17-2:
02       J17-3:
03       J17-4:
04       J17-5: GPIO
05       J17-6:
06       J17-7: GPIO I2C
07       J17-8: GPIO I2C
08       J17-9: GPIO I2C
09      J17-10: GPIO SPI
10      J17-11: GPIO SPI
11      J17-12: GPIO SPI
12      J17-13:
13      J17-14: GPIO
14       J18-1: GPIO PWM
15       J18-2: GPIO
16       J18-3:
17       J18-4:
18       J18-5:
19       J18-6: GPIO I2C
20       J18-7: GPIO PWM
21       J18-8: GPIO PWM
22       J18-9:
23      J18-10: GPIO SPI
24      J18-11: GPIO SPI
25      J18-12: GPIO
26      J18-13: GPIO UART
27      J18-14:
28       J19-1:
29       J19-2:
30       J19-3:
31       J19-4: GPIO
32       J19-5: GPIO
33       J19-6: GPIO
34       J19-7:
35       J19-8: GPIO UART
36       J19-9: GPIO
37      J19-10: GPIO
38      J19-11: GPIO
39      J19-12: GPIO
40      J19-13: GPIO
41      J19-14: GPIO
42       J20-1:
43       J20-2:
44       J20-3:
45       J20-4: GPIO
46       J20-5: GPIO
47       J20-6: GPIO
48       J20-7: GPIO
49       J20-8: GPIO
50       J20-9: GPIO
51      J20-10: GPIO
52      J20-11: GPIO
53      J20-12: GPIO
54      J20-13: GPIO
55      J20-14: GPIO

     

     

    I tried setting GPIO 48 (pin 7 on the Arduino shield) and it wouldn't work.

     

    If I used the echo command it worked, and using mraa-gpio get 48, it gave the current state (0 or 1) in response to the echo commands.

     

    So I'm a little puzzled ... more digging is required.

     

     

     

    mark

  • in reply to mcb1

    A little digging and this table shows that the mraa number and the GPIO number (and then the Arduino) are not the same.

    mraa: Intel Edison

     

    It seems mraa 33 is GPIO 48 and it works BUT.

    You can use either the echo or the mraa-gpio to set the pin or change it,

    BUT if you read the pin with get or getraw, you get a write error.

     

    root@edison:/sys/class/gpio/gpio48# /usr/bin/mraa-gpio getraw 33
Pin 33 = 0
root@edison:/sys/class/gpio/gpio48# echo 1 > value
-sh: echo: write error: Operation not permitted
root@edison:/sys/class/gpio/gpio48# /usr/bin/mraa-gpio set 33 1
root@edison:/sys/class/gpio/gpio48# echo 0 > value
root@edison:/sys/class/gpio/gpio48# /usr/bin/mraa-gpio getraw 33
Pin 33 = 0
root@edison:/sys/class/gpio/gpio48# echo 0 > value
-sh: echo: write error: Operation not permitted
root@edison:/sys/class/gpio/gpio48#

     

    Seems strange that a read (get) will lock out changing it but you can set it with one method and change it with the other ???

     

     

    mark

Reply
  • in reply to mcb1

    A little digging and this table shows that the mraa number and the GPIO number (and then the Arduino) are not the same.

    mraa: Intel Edison

     

    It seems mraa 33 is GPIO 48 and it works BUT.

    You can use either the echo or the mraa-gpio to set the pin or change it,

    BUT if you read the pin with get or getraw, you get a write error.

     

    root@edison:/sys/class/gpio/gpio48# /usr/bin/mraa-gpio getraw 33
Pin 33 = 0
root@edison:/sys/class/gpio/gpio48# echo 1 > value
-sh: echo: write error: Operation not permitted
root@edison:/sys/class/gpio/gpio48# /usr/bin/mraa-gpio set 33 1
root@edison:/sys/class/gpio/gpio48# echo 0 > value
root@edison:/sys/class/gpio/gpio48# /usr/bin/mraa-gpio getraw 33
Pin 33 = 0
root@edison:/sys/class/gpio/gpio48# echo 0 > value
-sh: echo: write error: Operation not permitted
root@edison:/sys/class/gpio/gpio48#

     

    Seems strange that a read (get) will lock out changing it but you can set it with one method and change it with the other ???

     

     

    mark

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