Button library
Macros | |
| #define | BUTTON_NOT_PUSHED 0 |
| #define | BUTTON_PUSHED 1 |
| #define | SWITCH_OFF 0 |
| #define | SWITCH_ON 1 |
Enumerations | |
| enum | button_index_t { BUTTON0, BUTTON1, BUTTON2, BUTTON3, NUM_BUTTONS } |
| enum | switches_index_t { SWITCH0, SWITCH1, NUM_SWITCHES } |
Functions | |
| void | switches_init (void) |
| void | switches_destroy (void) |
| void | buttons_init (void) |
| void | buttons_destroy (void) |
| int | get_button_state (const int button) |
| int | wait_until_button_state (const int button, const int state) |
| int | sleep_msec_button_pushed (const int button, const int msec) |
| void | sleep_msec_buttons_pushed (int button_states[], const int ms) |
| int | wait_until_button_pushed (const int button) |
| int | wait_until_button_released (const int button) |
| int | wait_until_any_button_pushed (void) |
| int | wait_until_any_button_released (void) |
| int | get_switch_state (const int switch_num) |
Detailed Description
Wrappers to simplify the use of buttons.
- Buttons are numbered 0..NUM_BUTTONS-1, and return values are BUTTON_PUSHED and BUTTON_NOT_PUSHED
- Switches are numbered 0..NUM_SWITCHES-1, and return values are SWITCH_ON and SWITCH_OFF.
- wait_ functions return early, i.e. as soon as the stated condition is true.
- sleep_ functions do not return early, i.e. always wait until the specified number of milliseconds.
An example of how to use this library.
#include <libpynq.h>
int main (void)
{
// initialise all I/O
pynq_init();
buttons_init();
printf("Waiting until button 0 is pushed...\n");
printf("Waited %d milliseconds\n\n", wait_until_button_pushed(0));
printf("Waiting until button 0 is released...\n");
printf("Waited %d milliseconds\n\n", wait_until_button_released(0));
// clean up after use
pynq_destroy();
return EXIT_SUCCESS;
}
Buttons can also be used through GPIO (see gpio.h and pinmap.h). Note that GPIO numbering (IO_BTN0..IO_BTN3) is then used instead of 0..NUM_BUTTONS-1 (BUTTON0..BUTTON3). GPIO return values are GPIO_LEVEL_LOW/HIGH instead of BUTTON_(NOT_)PUSHED.
Switches can also be used through GPIO (see gpio.h and pinmap.h). Note that GPIO numbering (IO_SW0..IO_SW1) is then used instead of 0..NUM_SWITCHES-1 (SWITCH0..SWITCH1). GPIO return values are GPIO_LEVEL_LOW/HIGH instead of SWITCH_ON/OFF.
Macro Definition Documentation
◆ BUTTON_NOT_PUSHED
◆ BUTTON_PUSHED
◆ SWITCH_OFF
◆ SWITCH_ON
Enumeration Type Documentation
◆ button_index_t
| enum button_index_t |
◆ switches_index_t
| enum switches_index_t |
Function Documentation
◆ buttons_destroy()
◆ buttons_init()
| void buttons_init | ( | void | ) |
◆ get_button_state()
| int get_button_state | ( | const int | button | ) |
Return the state of the button (BUTTON_(NOT_)PUSHED).
- Parameters
-
button The button the state of which is returned.
- Warning
- Fails with program exit when button is outside valid range.
- Fails with program exit when the direction of the button was not set to input (e.g. because buttons_init was not called before).
◆ get_switch_state()
| int get_switch_state | ( | const int | switch_num | ) |
◆ sleep_msec_button_pushed()
| int sleep_msec_button_pushed | ( | const int | button, |
| const int | msec | ||
| ) |
Check if the given button is pushed in msec milliseconds. The function does NOT return early.
- Parameters
-
button The button of which the state is monitored. msec The number of milliseconds to wait.
- Returns
- BUTTON_PUSHED or BUTTON_NOT_PUSHED.
- Warning
- Fails with program exit when button is outside valid range.
- Fails with program exit when the direction of the button was not set to input (e.g. because buttons_init was not called before).
◆ sleep_msec_buttons_pushed()
| void sleep_msec_buttons_pushed | ( | int | button_states[], |
| const int | ms | ||
| ) |
Check if any button is pushed in msec milliseconds. The function does NOT return early.
- Parameters
-
button_states The array of button states that are updated with BUTTON_PUSHED or BUTTON_NOT_PUSHED.
- Warning
- Fails with program exit when the direction of any button was not set to input (e.g. because buttons_init was not called before).
◆ switches_destroy()
◆ switches_init()
| void switches_init | ( | void | ) |
◆ wait_until_any_button_pushed()
| int wait_until_any_button_pushed | ( | void | ) |
Wait until any button is not pushed (which may be immediately).
- Returns
- Wait until any button is pushed, return the number of the button that was pushed (0..NUM_BUTTONS-1).
- Warning
- Fails with program exit when the direction of any button was not set to input (e.g. because buttons_init was not called before).
◆ wait_until_any_button_released()
| int wait_until_any_button_released | ( | void | ) |
Wait until the given button is not pushed (which may be immediately).
- Returns
- Wait until any button is released, return the number of the button that was pushed (0..NUM_BUTTONS-1).
- Warning
- Fails with program exit when the direction of any button was not set to input (e.g. because buttons_init was not called before).
◆ wait_until_button_pushed()
| int wait_until_button_pushed | ( | const int | button | ) |
Wait until the given button is pushed (which may be immediately).
- Parameters
-
button The button of which the state is monitored.
- Returns
- The number of milliseconds waited until the button was pushed.
- Warning
- Fails with program exit when button is outside valid range.
- Fails with program exit when the direction of the button was not set to input (e.g. because buttons_init was not called before).
Definition at line 168 of file buttons.c.
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◆ wait_until_button_released()
| int wait_until_button_released | ( | const int | button | ) |
Wait until the given button is not pushed (which may be immediately).
- Parameters
-
button The button of which the state is monitored.
- Returns
- The number of milliseconds waited until the button was released.
- Warning
- Fails with program exit when button is outside valid range.
- Fails with program exit when the direction of the button was not set to input (e.g. because buttons_init was not called before).
Definition at line 173 of file buttons.c.
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◆ wait_until_button_state()
| int wait_until_button_state | ( | const int | button, |
| const int | state | ||
| ) |
Wait until the given button is in state (which may be immediately).
- Parameters
-
button The button of which the state is monitored. state The state that is waited for. Must be BUTTON_PUSHED or BUTTON_NOT_PUSHED.
- Returns
- The number of milliseconds that was waited.
- Warning
- Fails with program exit when button is outside valid range.
- Fails with program exit when the direction of the button was not set to input (e.g. because buttons_init was not called before).
Definition at line 85 of file buttons.c.
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