LPC1114 红外遥控解码程序(RC5 )

/********************************************************************
;
;modified LPC1114 sample code
;
; RC5 format:
; | S | F | C | 5 sytem bits | 6 command bits |
; | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 1 |
;
; —–+ +-+ +-+ +-+ +-+ +-+ +—+ +-+ +—+ +-+ +-+ +-+ +—-
; | | | | | | | | | | | | | | | | | | | | | | | |
; +-+ +—+ +-+ +-+ +-+ +-+ +-+ +—+ +-+ +-+ +-+ +-+
;
********************************************************************/
#include “LPC11xx.h” /* LPC11xx Peripheral Registers */
#define RC5_INPUT_PIN (1<< 0x01)
#define MIN_HALF_BIT 640 // 640 us
#define HALF_BIT_TIME 889 // 889 us
#define MAX_HALF_BIT 1140 // 1140 us
#define MIN_FULL_BIT 1340 // 1340 us
#define FULL_BIT_TIME 1778 // 1778 us
#define MAX_FULL_BIT 2220 // 2220 us
unsigned char RC5_System; // Format 1 E/N ts4 s3 s3 s1 s0
unsigned char RC5_Command; // Format 00c5 c4 c3 c2 c1 c0
unsigned char RC5_flag;
static signed int low_time;
static signed int high_time;
static unsigned char half_bit;
static unsigned char sys; // system byte
static unsigned char cmd; // Command byte
void RC5_Init(void)
{
//GPIO setup
//assign input for IR sensor
LPC_GPIO0->DIR &= ~(RC5_INPUT_PIN);
LPC_IOCON->PIO0_1 |= (1<<5); //turn on hysteresis
LPC_SYSCON->SYSAHBCLKCTRL |= (1<<6);//enable GPIO clock
NVIC_EnableIRQ(EINT0_IRQn);
//timer16 0 setup
LPC_SYSCON->SYSAHBCLKCTRL |= (1<<7);
LPC_TMR16B0->PR= 48; // prescaler 48, timer runs at 48 MHz / 48 = 1 MHz
LPC_TMR16B0->MR0 = 12000; //load match register 0
LPC_TMR16B0->MCR = 3; // Interrupt and Reset on MR0
NVIC_EnableIRQ(TIMER_16_0_IRQn);
LPC_GPIO0->IS &= ~(0x1<<0x01);//interrupt sense – 0 = edge sensitive
LPC_GPIO0->IBE |= 0x1<<0x01; //interrupt both edges - 1 = both edges
LPC_GPIO0->IE |= ( 0x1 << 0x01); //interrupt enable
LPC_TMR16B0->TCR = 1; //Start timer
}
static void RC5_Shift_Bit(char val)
{
if (sys & 0x80)
{
if (cmd & 0x80) // command full ?
{
sys = 0; // yes, ERROR
cmd = 0;
}
else
cmd = (cmd << 1) | val; // shift command
}
else
sys = (sys << 1) | val; // shift system
}
/************************************************************************
; RC5_Decode (we only take action at a rising edge)
;
; Half(prev) Bit Low Time High Time Action New Half Bit
; ——————————————————————-
; 0 0 0 Shift 0 0
; 0 0 1 Shift 1 1
; 0 1 0 -ERROR- *
; 0 1 1 Shift 1,0 0
; 1 0 0 Shift 1 1
; 1 0 1 -ERROR- *
; 1 1 0 Shift 1,0 0
; 1 1 1 -ERROR- *
;
***********************************************************************/
static void RC5_Decode(void)
{
unsigned char action;
action = half_bit << 2;
// Check High Time
if ((high_time > MIN_FULL_BIT) && (high_time < MAX_FULL_BIT))
action = action | 1; // high_time = long
else if (!((high_time > MIN_HALF_BIT) && (high_time < MAX_HALF_BIT)))
{
sys = 0; // RC5 ERROR
cmd = 0;
return;
}
// Check Low Time
if ((low_time > MIN_FULL_BIT) && (low_time < MAX_FULL_BIT))
action = action | 2; // low_time = long
else if (!((low_time > MIN_HALF_BIT) && (low_time < MAX_HALF_BIT)))
{
sys = 0; // RC5 ERROR
cmd = 0;
return;
}
switch (action)
{
case 0:RC5_Shift_Bit(0); // short low, short high, shift 0
break;
case 1:RC5_Shift_Bit(1); // short low, long high, shift 1
half_bit = 1; // new half bit is true
break;
case 2:sys = 0; // long low, short high, ERROR
cmd = 0;
case 3:RC5_Shift_Bit(1); // long low, long high, shift 1,0
RC5_Shift_Bit(0);
break;
case 4:RC5_Shift_Bit(1); // short low, short high, shift 1
break;
case 5:sys = 0; // short low, long high, ERROR
cmd = 0;
break;
case 6:RC5_Shift_Bit(1); // long low, short high, shift 1,0
RC5_Shift_Bit(0);
half_bit = 0; // new half bit is false
break;
case 7:sys = 0; // long low, long high, ERROR
cmd = 0;
default: break; // invalid
}
}
void PIOINT0_IRQHandler(void)
{
uint32_t regVal;
LPC_TMR16B0->TCR = 0; //disable timer
regVal =LPC_GPIO0->MIS & (0x1<<0x01);//get interrupt status
if ( regVal )
{
if( (LPC_GPIO0->DATA & RC5_INPUT_PIN) == RC5_INPUT_PIN) // check rising or falling edge
{
if (sys == 0) // First pulse ?
{
low_time= HALF_BIT_TIME; // assume short low time
high_time = HALF_BIT_TIME; // assume short high time
half_bit= 1; // assume half bit is true
cmd = 0x02; // = 00000010, prepare command byte
}
else
low_time = LPC_TMR16B0->TC; // rising, so capture low time
RC5_Decode();
}
else
high_time = LPC_TMR16B0->TC; // falling, so capture high time
}
LPC_TMR16B0->TCR = 1; //enable timer
LPC_TMR16B0->TCR = 2; //reset timer
LPC_GPIO0->IC |= ( 0x1 << 0x01);//clear interrupt
LPC_TMR16B0->TCR = 1; //enable timer
}
void TIMER16_0_IRQHandler(void)
{
if ( LPC_TMR16B0->IR & 0x1 )
{
//timeout has occured.
if (cmd & 0x80) // command full ?
{
RC5_Command = cmd & 0x7F; // OK ! Save command byte
RC5_System = sys; // save system byte
RC5_flag = 1; // set event to application
}
sys = 0;
cmd = 0;
}
LPC_TMR16B0->IR = 1; // clear interrupt flag
}

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LPC1114 红外遥控解码程序(RC5 )

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