irstate.h

这是一个SIGMA方案的PMP播放器的UCLINUX程序,可播放DVD,VCD,CD MP3...有很好的参考价值.

#ifndef _IR_STATE_H
#define _IR_STATE_H

#define IR_PIO              1       /* PIO0 pin used for ir sensor */
/////////////////////////////////////////////////////////////////////////////////////////
// ir state machine:

// PIO 1 is high, we can proceed to state 2 only when PIO 1 goes low
#define IR_STATE_WAIT_FOR_COMMAND_START		1

// PIO 1 is low, save the time (t0) at this moment and go to state 3
#define IR_STATE_COMMAND_START				2

// PIO 1 is low, we can proceed to state 4 only when PIO 1 goes high
#define IR_STATE_COMMAND					3 
 
// PIO 1 is high, current time = t1, if (t1-t0) < 8ms go back to state 1,
// else proceed to state 5
#define IR_STATE_COMMAND_END				4

// PIO 1 is high, save the time (t0) at this moment and go to state 6
#define IR_STATE_LEADER_PULSE_START			5

// PIO 1 is high, we can only proceed to state 7 when PIO 5 goes low
#define IR_STATE_LEADER_PULSE				6

// PIO 1 is low, current time = t1, if (t1-t0) < 3.5ms, then the last key was kept
// pressed down, go to state 8, else go to state 12
#define IR_STATE_LEADER_PULSE_END			7

// PIO 1 is low, we can proceed to state 9 only when PIO 1 goes high
#define IR_STATE_REPEAT_PULSE_START			8

// PIO 1 is low, set bit_position to 31, go to state 13, save current time as t0
#define IR_STATE_READ_SCAN_CODE				12

// PIO 1 is low, we can only proceed to state 14 when PIO 1 goes high
#define IR_SUBSTATE_READ_BIT_START			13

// PIO 1 is high, we can only go to state 15 when PIO 1 goes low
#define IR_SUBSTATE_READ_BIT_HIGH			14

// PIO 1 is low, current time = t1, if (t1-t0) > 1.75ms 
// scan_code |= (1 << bit_position)
// decrement bit position, if bit_posiion < 0, go to state 1, else go to state 13
#define IR_SUBSTATE_READ_BIT_LOW			15 

// error recovery state - ignore all input for 70ms
#define IR_STATE_ERROR_RECOVERY				20

typedef struct tagIR_STATE
{
	int state;		// initialize to 1
	int timer_load;		// initialize to value in TIMER_LOAD_REG
	int timer_scale;        // timer prescale value
	int repeat;             // no initialization required
	int scan_code;		// no initialization required
	int bit_position;	// no initialization required
	int t0;			// no initialization required
	int error_recovery;	// no initialization required
	int release_timeout;	// no initialization required
} IR_STATE;

extern IR_STATE ir_state;

#define IR_REPEAT 4

// call this function for each pio interrupt
// return 0 or 1 idf a scancode has been received.
int ir_pio();
int ir_state_machine (IR_STATE *ir_state);

//#define POLL_USING_TIMER 1
//#define USE_FIQ	1
#define USE_IRQ 1

void ir_init(void);

#endif