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How to control a GPIO:
How to control a GPIO:


  cd /sys/class/gpio
:{| class="wikitable"
  echo 44 >export             // create new directory
|1. <code>''cd /sys/class/gpio''</code>
  cd gpio44                    // go into this directory
|-
  cat direction                // show if GPIO is used as an input or an output
|2. create new directory: <code>''echo 44 >export ''</code>
  out
|-
  echo 1 >value                // change output to '1'=high
|3. go into this directory: <code>''cd gpio44''</code>
  echo in >direction          // change GPIO to input
|-
  cat value                    // show input value
|4. show if GPIO is used as an input or an output: <code>''cat direction''</code>
  0                            // '0' = low
|-
|5. change output to '1'=high: <code>''echo 1 >value''</code>
|-
|6. change GPIO to input: <code>''echo in >direction''</code>
|-
|7. show input value: <code>''cat value''</code>
|} 
 
==PLD==
==PLD==



Latest revision as of 09:28, 8 August 2012

GPIOs

Mapping

 In the following sheet you can find the GPIOs and their linux-number
 

Control

How to control a GPIO:

1. cd /sys/class/gpio
2. create new directory: echo 44 >export
3. go into this directory: cd gpio44
4. show if GPIO is used as an input or an output: cat direction
5. change output to '1'=high: echo 1 >value
6. change GPIO to input: echo in >direction
7. show input value: cat value

PLD

Development Software

To write your own VDHL-code you can use the ispLEVER Classic Software from Lattice ([1]


You also need a programmer (e.g. HW-USBN-2A from Lattice) to deploy the VHDL-Code on your PLD.

After installing the software and the drivers for your programmer you can start a new project.

Programming example

You can find a demo-project here:media:PLD-demo.zip

You have to download the *.jed-File with the programmer to your PLD.

 In the constraint editor of ispLEVER you can define, which input X_VAR1 is.
 In this example GPIO E is defined as X_VAR1. If you define GPIO E as an
 output and set GPIO E high, the PLD LED should flash red.