Device driver interface for the Hynitron CST816S touch screen. More...

Detailed Description

Device driver interface for the Hynitron CST816S touch screen.

The CST816S is a touch sensor from Hynitron with integrated gesture detection. It is able to measure both the position of a single finger and a number of basic gestures. The PineTime board has one of these for the touch screen.

Documentation about the specifics is very limited and most of this driver is based on experimenting with the chip and from community effort on the PineTime.

Two things about the driver are noteworthy:

It only responds to I2C commands after an event, such as a touch detection. Do not expect it to respond on init. Instead after a touch event, it will assert the IRQ and respond to I2C reads for a short time.
While it should be able to detect multiple finger events, this version of the chip always returns only a single finger event and a gesture.

Reading the display data multiple times during a single event will return the last sampled finger position.

Files
file	cst816s_internal.h
	Internal constants for cst816s.

file	cst816s_params.h
	Default configuration for the CST816S touch screen driver.

file	cst816s_touch_dev.h
	Definition of the driver for the touch_dev generic interface.

file	cst816s.h
	Device driver interface for the CST816S touch screen.

Data Structures
struct	cst816s_touch_data_t
	cst816s touch event data More...

struct	cst816s_params_t
	cst816s driver struct More...

struct	cst816s_t
	cst816s device descriptor More...

Typedefs
typedef void(*	cst816s_irq_cb_t) (void *arg)
	callback definition

Enumerations
enum	cst816s_touch_t { CST816S_TOUCH_DOWN = 0 , CST816S_TOUCH_UP = 1 , CST816S_TOUCH_CONTACT = 2 }
	cst816s touch event touch state More...

enum	cst816s_gesture_t { CST816S_GESTURE_NONE = 0x00 , CST816S_GESTURE_SLIDE_DOWN = 0x01 , CST816S_GESTURE_SLIDE_UP = 0x02 , CST816S_GESTURE_SLIDE_LEFT = 0x03 , CST816S_GESTURE_SLIDE_RIGHT = 0x04 , CST816S_GESTURE_SINGLE_CLICK = 0x05 , CST816S_GESTURE_DOUBLE_CLICK = 0x0b , CST816S_GESTURE_LONG_PRESS = 0x0c }
	CST816S Gesture types. More...

enum	{ CST816S_OK = 0 , CST816S_ERR_IRQ = -1 }
	Status and error return codes. More...

Functions
int	cst816s_init (cst816s_t dev, const cst816s_params_t params, cst816s_irq_cb_t cb, void *arg)
	Initialize the given cst816s device.

int	cst816s_read (const cst816s_t dev, cst816s_touch_data_t data)
	Read touch data from the cst816s device.

Variables
const char *	cst816s_gesture_str []
	string versions of the cst816 gestures

Typedef Documentation

◆ cst816s_irq_cb_t

typedef void(* cst816s_irq_cb_t) (void *arg)

callback definition

Definition at line 60 of file cst816s.h.

Enumeration Type Documentation

◆ anonymous enum

anonymous enum

Status and error return codes.

Enumerator
CST816S_OK	everything was fine
CST816S_ERR_IRQ	IRQ initialization error.

Definition at line 126 of file cst816s.h.

◆ cst816s_gesture_t

enum cst816s_gesture_t

CST816S Gesture types.

Enumerator
CST816S_GESTURE_NONE	no gesture detected
CST816S_GESTURE_SLIDE_DOWN	downward slide detected
CST816S_GESTURE_SLIDE_UP	upward slide detected
CST816S_GESTURE_SLIDE_LEFT	left slide detected
CST816S_GESTURE_SLIDE_RIGHT	right slide detected
CST816S_GESTURE_SINGLE_CLICK	single click detected
CST816S_GESTURE_DOUBLE_CLICK	double click detected
CST816S_GESTURE_LONG_PRESS	long press detected

Definition at line 74 of file cst816s.h.

◆ cst816s_touch_t

enum cst816s_touch_t

cst816s touch event touch state

Enumerator
CST816S_TOUCH_DOWN	Touch press.
CST816S_TOUCH_UP	Touch release.
CST816S_TOUCH_CONTACT	Touch contact.

Definition at line 65 of file cst816s.h.

Function Documentation

◆ cst816s_init()

int cst816s_init	(	cst816s_t *	dev,
		const cst816s_params_t *	params,
		cst816s_irq_cb_t	cb,
		void *	arg
	)

Initialize the given cst816s device.

Parameters

[out]	dev	device descriptor of the given cst816s device
[in]	params	static configuration parameters
[in]	cb	callback for the cst816s event interrupt, may be NULL
[in]	arg	extra argument passed to the event interrupt.

Returns: CST816S_OK on success; CST816S_ERR_IRQ on IRQ initialization error

◆ cst816s_read()

int cst816s_read	(	const cst816s_t *	dev,
		cst816s_touch_data_t *	data
	)

Read touch data from the cst816s device.

Parameters

[in]	dev	device descriptor
[out]	data	Touch data

Returns: 0 on success; negative on I2C access error

Detailed Description

Files

Data Structures

Typedefs

Enumerations

Functions

Variables