Depending on when in the boot process a module is needed it has to be initialized earlier or later. For instance, on the NGW the three subdirectories a, b and sys are in that directory. This is the standard method when opening files on Linux. By reading of and writing to those files, a user-space application can configure GPIOs. A GPIO should be configured in the board setup code. In other words put all code that is not especially reserved for other places here. The hexdump program will print out the four bytes as a nice hexadecimal value.

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The data structure is defined as: Access to a GPIO is possible from two places. The specified partitions are tied to parts. Other terms and product names may be trademarks of others.

Its main purpose is to turn something on or off.

Avvr32 device types are listed in the same file. The device id in combination with the name must be unique. Depending on the event type, there are different event codes.

By writing a nonzero value the possible range is from 0 to the LED gpuo activated. The device datasheet lists available TWI modules.


Following steps are needed to add a new board configuration.

To get input states of a pin to user-space, use the gpio-keys driver. Take a look at chapter 3 on how to configure GPIOs. This means only if a GPIO has changed its status since the last read. A user-space application should therefore first read the entire file, modify it and then write the entire buffer back.

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The maximum size of an attribute file is the size of a page bytes on the AVR32, but should always be read out by using a library function as getpagesize or similar. For instance, if we select the timer trigger, two more attributes are available: Therefore, if LED is mentioned in this chapter, the term is exchangeable to any other peripheral. The information in this document is provided in connection with Atmel products. However, these are only optional functions. For example an adaptation is necessary if the pin multiplexing should be different or unused peripheral pins should be used for other things.

The available module functions for each pin are listed in the device datasheet.

View detail for AVR32744: 32-bit AVR AP7 Linux Custom Board Support

For instance, on the NGW the three subdirectories a, b and sys are in that directory. A proper board code can also be submitted upstream in order to be added to the official kernel. Currently most of the boardspecific initialization code is gathered in a setup.


When we want to configure these settings in an application and not from the shell or a shell scriptthe following considerations must be taken into account: To see all available options run the application with the —h flag.

This chapter is here because many use this interface already and maybe do not want to switch to another solution. This entry could look like this: The hexdump program will print out the four bytes as a nice hexadecimal value.

These examples can be used to form a new custom board. This interface is AVR32 specific and it is not available on other platforms. Here, we have full control of all the pin settings. Use the —n flag to set the non-blocking method. For the above partitions the linu would be initialized like this: