alt_touchscreen.h

基于NIOSII软核的触摸屏驱动软体.采用的是AD7843触摸屏数字转换器

 *
 *        D) Software-sync and reentrancy issues with an ISR-updated
 *            structure is always something to be very, very careful
 *            about.
 *
 *    Really: A, just make our SPI ISR-routine more
 *    complicated.  This needs to be a little state-machine that
 *    remembers things like: "Am I currently sampling X or Y?" and 
 *    "What phase of sample-aquisition am I currently in?"
 *
 *    Issues B and C can safely be ignored.
 * 
 *    Issue D (reentrancy and synchronization) makes the public "get
 *    me a sample" access routine more complex..we have to be careful
 *    not to grab an incoherent sample.  But programmers have ways of
 *    guarding against this kind of thing, as you will see.
 * 
 ****************************************************************/
#include "sys/alt_alarm.h"
#include "alt_types.h"

typedef struct alt_touchscreen_axis_scaler_struct 
{
  int input_A;
  int input_B;
  int output_A;
  int output_B;
} alt_touchscreen_axis_scaler;

typedef struct alt_touchscreen_surface_scaler_struct
{
  alt_touchscreen_axis_scaler x;
  alt_touchscreen_axis_scaler y;
} alt_touchscreen_surface_scaler;

typedef enum alt_touchscreen_axis_swap_choice_enum
  { 
    ALT_TOUCHSCREEN_NO_SWAP_XY,
    ALT_TOUCHSCREEN_SWAP_XY
  } alt_touchscreen_axis_swap_choice;


typedef enum alt_touchscreen_callback_trigger_enum
  {
    ALT_TOUCHSCREEN_CALLBACK_NEVER,
    ALT_TOUCHSCREEN_CALLBACK_ON_PEN_UP,
    ALT_TOUCHSCREEN_CALLBACK_ON_PEN_DOWN,
    ALT_TOUCHSCREEN_CALLBACK_ON_PEN_MOVE
  } alt_touchscreen_callback_trigger;

typedef struct alt_touchscreen_scaled_pen_data_struct 
{
  int pen_down;
  int x;
  int y;
} alt_touchscreen_scaled_pen_data;

typedef struct alt_touchscreen_pen_adc_data_struct 
{
  volatile int x;
  volatile int y;
} alt_touchscreen_pen_adc_data;

typedef void (*alt_touchscreen_event_callback_func)
     (int pen_down, int x, int y, void*);

typedef struct alt_touchscreen_even_flag_group_struct
{
  volatile int pen_up_event_flag;
  volatile int pen_down_event_flag;
  volatile int pen_move_event_flag;
} alt_touchscreen_event_flag_group;

typedef struct alt_touchscreen_callback_registry_entry_struct
{
  alt_touchscreen_callback_trigger     trigger;
  alt_touchscreen_event_callback_func  callback_func;
  void*                                context;
} alt_touchscreen_callback_registry_entry;

#define ALT_TOUCHSCREEN_CALLBACK_REGISTRY_NUM_ENTRIES 10

typedef struct alt_touchscreen_callback_registry_struct
{
  alt_touchscreen_callback_registry_entry registry 
    [ALT_TOUCHSCREEN_CALLBACK_REGISTRY_NUM_ENTRIES];
} alt_touchscreen_callback_registry;


typedef struct alt_touchscreen_pen_state_struct
{
  volatile int          pen_down;
  volatile int          previous_pen_down;
  volatile int          pen_detect_counter;
  volatile int          sample_number;
} alt_touchscreen_pen_state;

typedef struct alt_touchscreen_hardware_struct
{
  alt_u32 spi_controller_base;
  alt_u32 pen_detect_pio_base;
  alt_u32 spi_controller_irq_number;
} alt_touchscreen_hardware;


#define NUM_SAMPLE_MACHINE_PHASES 5

typedef struct alt_touchscreen_sample_machine_struct
{
  int sample_phase;
  alt_u8 scheduled_commands     [NUM_SAMPLE_MACHINE_PHASES]; 
  alt_u8 link_with_next_command [NUM_SAMPLE_MACHINE_PHASES]; 
  alt_u8 rxdata_values 	        [NUM_SAMPLE_MACHINE_PHASES]; 
} alt_touchscreen_sample_machine;

typedef struct alt_touchscreen_spi_isr_context_struct
{
  alt_touchscreen_hardware*         hw;
  alt_touchscreen_sample_machine*   sample_machine;
  alt_touchscreen_pen_adc_data*     adc_data;
  alt_touchscreen_pen_state*        pen_state;
  alt_touchscreen_event_flag_group* event_flags;
} alt_touchscreen_spi_isr_context;

typedef struct alt_touchscreen_alarm_context_struct 
{
  int nticks;
  alt_touchscreen_hardware*         hw;
  alt_touchscreen_sample_machine*   sample_machine;
  alt_touchscreen_pen_state*        pen_state;
  alt_touchscreen_event_flag_group* event_flags;
} alt_touchscreen_alarm_context;
  
typedef struct alt_touchscreen_struct
{
  ////////////////
  // NOTE: THIS ENTIRE STRUCTURE IS PRIVATE.
  //
  //   It may be tempting for application-programmers to
  // rummage-around inside this structure and get things like x-y
  // coordinates or pen up/down status directly.  DON'T.   You are not
  // guaranteed to get a coherent (or even valid) sample unless you
  // use the provided public access routines.
  

  // Data Aquisition
  alt_alarm                         alarm;
  alt_touchscreen_hardware          hardware;
  alt_touchscreen_sample_machine    sample_machine;
  alt_touchscreen_pen_adc_data      pen_adc_data;
  alt_touchscreen_pen_state         pen_state;
  alt_touchscreen_event_flag_group  event_flags;

  // Interrupt-interface
  alt_touchscreen_spi_isr_context   spi_isr_context;
  alt_touchscreen_alarm_context     alarm_context;

  // Application interface
  alt_touchscreen_callback_registry callback_registry;

  // Coordinate mapping 
  alt_touchscreen_surface_scaler    surface_scaler;
  alt_touchscreen_axis_swap_choice  swap_xy;

} alt_touchscreen;

int alt_touchscreen_init (alt_touchscreen* screen,
			  alt_u32 spi_controller_base,
			  alt_u32 spi_controller_irq_number, 
			  alt_u32 pen_detect_pio_base,
			  int     samples_per_second,
			  alt_touchscreen_axis_swap_choice swap_xy );

void alt_touchscreen_stop (alt_touchscreen* screen);

unsigned int alt_touchscreen_get_pen (alt_touchscreen* screen,
				      int* pen_down,
				      int* x,
				      int* y);

int alt_touchscreen_register_callback_func (
    alt_touchscreen*                         screen,    
    alt_touchscreen_callback_trigger         callback_type,
    alt_touchscreen_event_callback_func      callback_func,
    void*                                    context	   );

void alt_touchscreen_event_loop_update (alt_touchscreen* screen);

void alt_touchscreen_calibrate_upper_right 
(
 alt_touchscreen* screen,
 unsigned int x_adc_value,
 unsigned int y_adc_value,
 int x_screen_coordinate,
 int y_screen_coordinate
 );

void alt_touchscreen_calibrate_lower_left
(
 alt_touchscreen* screen,
 unsigned int x_adc_value,
 unsigned int y_adc_value,
 int x_screen_coordinate,
 int y_screen_coordinate
 );

#endif // __ALT_TOUCHSCREEN_H_DEFINED