1GPIO 2-Pin Test
2###############
3
4This application tests the GPIO subsystem using a hardware configuration
5where two GPIOs are directly wired together.  The test pins are
6identified through a test-specific devicetree binding in the `dts/`
7subdirectory, implemented for specific boards by overlay files in the
8`boards/` directory.
9
10For some boards `src/main.c` may also need to be extended to configure
11the selected pins for use as GPIOs.
12
13Only boards for which an overlay is present can pass this test.  Boards
14without an overlay, or for which the required wiring is not provided,
15will fail with an error like this:
16
17    Validate device GPIO_0
18    Check GPIO_0 output 2 connected to input 3
19    FATAL output pin not wired to input pin? (out high => in low)
20
21No special build options are required to make use of the overlay.
22