I am using CAN protocol controller and it is connected via Avalon Bus to
the Nios II processor. The problem is that every time I try to give
Transmission Request CAN controller goes to the reset mode and
transmits nothing. What could be the reason for that?

The code I used is below:

////*Configuration and Initialization *////

/*Controller to reset-mode, register 0*/
IOWR_8DIRECT(CAN_CONTROLLER_BASE,0 ,0x21 );
usleep(1);

usleep(1);
/*Initialize clock divider, register 31*/
IOWR_8DIRECT(CAN_CONTROLLER_BASE,124 ,0x8 );

usleep(1);
/*Acceptance code, register 4*/
IOWR_8DIRECT(CAN_CONTROLLER_BASE,16 ,0xFF );

usleep(1);
/*Acceptance mask, register 5*/
IOWR_8DIRECT(CAN_CONTROLLER_BASE,20 ,0xFF );

usleep(1);
/*Bus timing 0, register 6 */
IOWR_8DIRECT(CAN_CONTROLLER_BASE,24 ,0x0 );

/*Bus timing 1, register 7 */
IOWR_8DIRECT(CAN_CONTROLLER_BASE,28 ,0x53 ); //0x27


usleep(1);
/*Operation mode, register 0*/
IOWR_8DIRECT(CAN_CONTROLLER_BASE,0,0x20);
usleep(2000000);

////*End of initialization *////

///*The code for packet transmission*///

/*identifier 1, register 10*/
IOWR_8DIRECT(CAN_CONTROLLER_BASE,40,0xFF);

/*identifier 2 (DLC=8), register 11*/
IOWR_8DIRECT(CAN_CONTROLLER_BASE,44,0x28);

/* data to databuffer 1, register 12*/
IOWR_8DIRECT(CAN_CONTROLLER_BASE,48,0x58);

/*transmission request, register 1*/
IOWR_8DIRECT(CAN_CONTROLLER_BASE,4,0x01);
usleep(1000000);

///*End of the code for packet transmission*///