caminterface.c

mg128＋Ov7620实现图象采集

/***********************************************************
	Module Name: CamInterface.c
	Module Date: 04/12/2004
	Module Auth: John Orlando
	
	Description: This file is responsible for providing an
	interface to the OV6620 camera hardware.  This includes
	an interface to CamInterface.S for certain low-level,
	optimized camera access routines.
    
    Revision History:
    Date        Rel Ver.    Notes
    4/10/2004      0.1     Module created
    6/30/2004      1.0     Initial release for Circuit Cellar
                           contest.
    11/15/2004     1.2     ifdef'd out the resetCam routine, since
                           resetting the cam now causes the OV6620's
                           clock to not be output (we have to start
                           it up after each reset with the external
                           tiny12 processor).
    1/16/2005      1.4     Ensure that the TCCR1B register is set so
                           nothing is clocking timer1 at startup.                             
***********************************************************/

/*	Includes */
#include <avr/interrupt.h>
#include <avr/signal.h>
#include <avr/sleep.h>
#include <avr/eeprom.h>
#include <stdlib.h>
#include <string.h>
#include "CommonDefs.h"
#include "CamInterface.h"
#include "Utility.h"
#include "UIMgr.h"
#include "Executive.h"
#include "UartInterface.h"



#define CAM_G_BUS          	PINC
#define CAM_G_BUS_DIR      	DDRC
#define CAM_RB_BUS          PINA
#define CAM_RB_BUS_DIR 		DDRA

#define CAM_CONTROL_PORT     PORTD
#define CAM_CONTROL_PORT_DIR DDRD



/*  Extern Variables */
/* These two buffers hold the current and previous lines
of pixel data.  They are sized to the worst case scenario,
where the color changes between every pixel (unrealistic).
The format of each buffer is for all the even bytes to hold
the run-length, and the odd bytes to hold the color data. */

/* In addition, if we are in frameDump mode, we use these buffers
to store the acquired line data...we are actually grabbing ALL of the
pixels in a line (176) instead of the 88 we get normally during tracking.
But since we have enough to hold 88-RLE blocks, we already have the 176
allocated for this... */
unsigned char currentLineBuffer[LENGTH_OF_LINE_BUFFER];
unsigned char previousLineBuffer[LENGTH_OF_LINE_BUFFER];/*176*/

/*  Extern Functions */
/* These functions are located in assembly files, and thus
must be externed here so they can be referenced in the source below. */
extern void CamIntAsm_waitForNewDumpFrame(unsigned char *pCurrBuffer, unsigned char *pPrevBuffer);
extern void CamIntAsm_acquireDumpLine(unsigned char *pCurrBuffer, unsigned char *pPrevBuffer);

/***********************************************************
	Function Name: CamInt_init
	Function Description: This function is responsible
	for initializing the camera interface.  This includes
	setting up the i/o ports that are used to read the
	camera busses, as well as resetting the camera.
	Inputs:  none
	Outputs: none
***********************************************************/	
void CamInt_init(void)
{

	CAM_CONTROL_PORT_DIR &= 0xFB;   /* make sure bit2 is clear (input) VSYNC interrupt*/
	//CAM_CONTROL_PORT &= 0x7F;   /* set reset line low */
	CAM_G_BUS_DIR &= 0x00;  /* 8-bit G bus all inputs      PortC*/
    DDRB |= 0x0A;  /* disable the pull-up on PB1 and PB3 */
	CAM_RB_BUS_DIR &= 0x00;  /* 8-bit RB bus all inputs    PortA*/
	
    /* ensure that timer1 is disabled to start...eventually, when PCLK needs
    to feed timer1 through the external counter, it will be enabled on an
    "as needed" basis...*/
	TCCR1B &= ~( (1<<CS12)|(1<<CS11)|(1<<CS10) );
	
	/* we'll turn on the interrupt after we assign the initial TCNT value */
	
	/* set up External Interrupt1 to interrupt us on rising edges (HREF)...
	this is needed to indicate when the first pixel of each line is about to start, so
	we can synch up with it...this interrupt will be disabled once HREF goes high */
	
	EICRA |= (1<<ISC31) | (1<<ISC30);  /* rising edge interrupt *///EICRA
	/* the interrupt will be enabled when we are ready to detect the rising edge of
	HREF...its now primed and ready to go */
	
	/* set up External Interrupt0 to interrupt us on rising edges (VSYNC) */
	EICRA |= (1<<ISC21) | (1<<ISC20);	/* rising edge interrupt */ 
	EIMSK |= (1<<INT2);    /* VSYNC interrupt request enabled */
	
	/* set up TimerO to count and be clocked from an external pulse source
	(HREF) on falling edges...eventually, we need to enable the interrupt
	for this!  FIX THIS */
	TCCR2 = (1<<CS02)|(1<<CS01)|(0<<CS00);
	
	/* setting up the PCLK counter with Timer1 will be done right after
	we start receiving pixels in each line...we sacrifice the first pixel
	in each line, but we'll account for it...*/
	
	/* set up the mega8 so that its sleep mode puts it in an IDLE sleep
	mode, where it can wake up as fast as possible */
	set_sleep_mode(SLEEP_MODE_IDLE);
	/* umm....we need to actually enable the sleep mode...*/
	MCUCR |= (1<<SE);
	
	


}

/***********************************************************
	Function Name: CamInt_resetCam
	Function Description: This function is responsible
	for resetting the camera.  This is accomplished by
	toggling the reset line on the OV6620 for ~100 mS.
	Inputs:  none
	Outputs: none
    IMPORTANT NOTE: This function has effectively been removed
    since resetting the camera now causes the camera to not
    output the clock signal.  Thus, if we reset the cam, the
    AVR has no clock, and thus doesn't run...
***********************************************************/	
void CamInt_resetCam(void)
{

#if 0
	CAM_CONTROL_PORT |= (1<<CAM_RESET_LINE); /* cam reset line high */
	Utility_delay(500);
	CAM_CONTROL_PORT &= (0<<CAM_RESET_LINE); /* cam reset line low */
	Utility_delay(100);
#endif    
}