initialization.c

bf537 CAN接口测试程序

#include "CAN_RX.h"

/*********************************************************************************
**																				**
** Init_PLL -	Configures the PLL so that the CAN BRP can easily be derived.	**
**				Sets Core Clock (CCLK) to 450MHz and System Clock (SCLK) to		**
**				112.5MHz.														**
**																				**
*********************************************************************************/
void Init_PLL()
{
	*pPLL_CTL = SET_MSEL(18);	/* (25MHz Xtal x (MSEL=18))::CCLK=450MHz		*/
	idle();
	
	*pPLL_DIV = SET_SSEL(4);	/* (450MHz/(SSEL=4))::SCLK=112.5MHz				*/
	ssync();
} /* end Init_PLL																*/


/*********************************************************************************
**																				**
** Init_Port -	Sets up the PORTs for CAN use and configures the PFx pins for	**
**				access to the on-board LEDs.  									**
**																				**
*********************************************************************************/
void Init_Port ()
{
	*pPORT_MUX = PJCE_CAN;	/* Enable CAN Pins On Port J						*/
	ssync();
		
	/* Configure Port F pins for LED access										*/
	*pPORTFIO_DIR   = PF6|PF7|PF8|PF9|PF10|PF11;	/* PF6-11 Output LEDs		*/
	ssync();
} /* End Init_Port ()															*/


/*********************************************************************************
**																				**
** Init_CAN_Timing -	Sets up the CAN TIMING and CLOCK registers.  Provided	**
**						comments indicate how to derive the BRP based on the	**
**						known SCLK value.  See CAN chapter of HRM for more		**
**						details regarding the CAN TIMING and CLOCK registers.	**
**																				**
*********************************************************************************/
void Init_CAN_Timing()
{
		/* ===================================================
		 * BIT TIMING:
		 * 
		 * CAN_TIMING : SJW = 3, TSEG2 = 3, TSEG1 = 4
		 * SJW <= TSEG2 <= TSEG1
		 * ===================================================
		 * CAN_CLOCK  : Prescaler (BRP)
		 * ===================================================
		 * 500kHz CAN Clock :: tBIT = 2us
		 * ===================================================
		 * tBIT = TQ * (1 + (TSEG1 + 1) + (TSEG2 + 1))
		 * 2e-6 = TQ * (1 + 5 + 4)
		 * TQ = 2e-7
		 *
		 * TQ = (BRP+1) / SCLK
		 * 2e-7 = (BRP+1) / 112.5e6
		 * (BRP+1) = 22.5
		 * BRP = 21.5 = ~22 = CAN_CLOCK
		 * ==================================================
		 * Set Bit Configuration Registers ...
		 * ==================================================*/
	*pCAN_TIMING = 0x0334;
	*pCAN_CLOCK  = 22;

	ssync();
} /* End Init_CAN_Timing()														*/


/*********************************************************************************
**																				**
** Init_CAN_Mailboxes -	Configures MB24 to transmit a specific message ID with	**
**						a message length of 1 byte.	 Configures MB7 to receive	**
**						a specific message ID.									**
**																				**
*********************************************************************************/
void Init_CAN_Mailboxes()
{
	short msgID;
	volatile char mbID;
	
	/* Mailbox 24 Will Transmit ACK back to transmitter via ID 0x007			*/
	msgID = 0x007;
	mbID  = 24;
	
	/* ID1, mask disabled, remote frame disable, 11 bit identifier				*/
	*(pCAN_MB_ID1(mbID)) = msgID << 2;
	*(pCAN_MB_LENGTH(mbID)) = 1;			/* DLC = 1 byte						*/

	/* Mailbox 7 Will Receive CAN Command From Transmitter via ID 0x411			*/
	msgID = 0x411;
	mbID  = 7;
	
	/* ID1, mask disabled, remote frame disable, 11 bit identifier				*/
	*(pCAN_MB_ID1(mbID)) = msgID << 2;
	ssync();
} /* End Init_CAN_Mailboxes()													*/


/*********************************************************************************
**																				**
** Init_Interrupts -	Assigns interrupt priorities for CAN TX and CAN RX.		**
**						Registers handlers for each and enables the	interrupt	**
**						in both the CEC and SIC.								**
**																				**
*********************************************************************************/
void Init_Interrupts()
{
	/* Configure Interrupt Priorities											*/
	*pSIC_IAR0 = 0x77777777;
	*pSIC_IAR1 = 0x07777777;	/* CAN RX IRQ   : 0=IVG7						*/
	*pSIC_IAR2 = 0x77777771;	/* CAN TX IRQ   : 1=IVG8						*/
	*pSIC_IAR3 = 0x77777777;
	
	/* Register Interrupt Handlers and Enable Core Interrupts					*/
	register_handler(ik_ivg7, CAN_RCV_HANDLER);
	register_handler(ik_ivg8, CAN_XMT_HANDLER);
	
	/* Enable SIC Level Interrupts												*/
	*pSIC_IMASK |= (IRQ_CAN_RX|IRQ_CAN_TX);
	
} /* end Init_Interrupts														*/