forked from Imagelibrary/rtems
83971c6f36
* clock/ckinit.c, console/console.c, include/bsp.h, include/coverhd.h, shmsupp/addrconv.c, shmsupp/getcfg.c, shmsupp/lock.c, shmsupp/mpisr.c, startup/bspclean.c, startup/bspstart.c, startup/linkcmds, timer/timer.c, timer/timerisr.S: URL for license changed.
107 lines
3.3 KiB
C
107 lines
3.3 KiB
C
/* Timer_init()
|
|
*
|
|
* This routine initializes the Z8036 timer on the MVME136 board.
|
|
*
|
|
* Input parameters: NONE
|
|
*
|
|
* Output parameters: NONE
|
|
*
|
|
* NOTE: This routine will not work if the optimizer is enabled
|
|
* for some compilers. The multiple writes to the Z8036
|
|
* may be optimized away.
|
|
*
|
|
* It is important that the timer start/stop overhead be
|
|
* determined when porting or modifying this code.
|
|
*
|
|
* COPYRIGHT (c) 1989-1999.
|
|
* On-Line Applications Research Corporation (OAR).
|
|
*
|
|
* The license and distribution terms for this file may be
|
|
* found in the file LICENSE in this distribution or at
|
|
* http://www.rtems.com/license/LICENSE.
|
|
*
|
|
* $Id$
|
|
*/
|
|
|
|
|
|
#include <bsp.h>
|
|
#include <zilog/z8036.h>
|
|
|
|
#define TIMER 0xfffb0000 /* address of Z8036 on MVME136 */
|
|
|
|
int Ttimer_val;
|
|
rtems_boolean Timer_driver_Find_average_overhead;
|
|
|
|
rtems_isr timerisr();
|
|
|
|
void Timer_initialize()
|
|
{
|
|
(void) set_vector( timerisr, 66, 0 ); /* install ISR */
|
|
|
|
Ttimer_val = 0; /* clear timer ISR count */
|
|
Z8x36_WRITE( TIMER, MASTER_INTR, 0x01 ); /* reset */
|
|
Z8x36_WRITE( TIMER, MASTER_INTR, 0x00 ); /* clear reset */
|
|
Z8x36_WRITE( TIMER, MASTER_INTR, 0xe2 ); /* disable lower chain, no vec */
|
|
/* set right justified addr */
|
|
/* and master int enable */
|
|
Z8x36_WRITE( TIMER, CT1_MODE_SPEC, 0x80 ); /* T1 continuous, and */
|
|
/* cycle/pulse output */
|
|
|
|
*((rtems_unsigned16 *)0xfffb0016) = 0x0000; /* write countdown value */
|
|
/*
|
|
Z8x36_WRITE( TIMER, CT1_TIME_CONST_MSB, 0x00 );
|
|
Z8x36_WRITE( TIMER, CT1_TIME_CONST_LSB, 0x00 );
|
|
*/
|
|
Z8x36_WRITE( TIMER, MASTER_CFG, 0xc4 ); /* enable timer1 */
|
|
|
|
Z8x36_WRITE( TIMER, CT1_CMD_STATUS, 0xc6 ); /* set INTR enable (IE), */
|
|
/* trigger command */
|
|
/* (TCB) and gate */
|
|
/* command (GCB) bits */
|
|
*((rtems_unsigned8 *)0xfffb0038) &= 0xfd; /* enable timer INTR on */
|
|
/* VME controller */
|
|
}
|
|
|
|
#define AVG_OVERHEAD 6 /* It typically takes 3.0 microseconds */
|
|
/* (6 countdowns) to start/stop the timer. */
|
|
#define LEAST_VALID 10 /* Don't trust a value lower than this */
|
|
|
|
int Read_timer()
|
|
{
|
|
/*
|
|
rtems_unsigned8 msb, lsb;
|
|
*/
|
|
rtems_unsigned32 remaining, total;
|
|
|
|
Z8x36_WRITE( TIMER, CT1_CMD_STATUS, 0xce ); /* read the counter value */
|
|
remaining = 0xffff - *((rtems_unsigned16 *) 0xfffb0010);
|
|
/*
|
|
Z8x36_READ( TIMER, CT1_CUR_CNT_MSB, msb );
|
|
Z8x36_READ( TIMER, CT1_CUR_CNT_LSB, lsb );
|
|
|
|
remaining = 0xffff - ((msb << 8) + lsb);
|
|
*/
|
|
total = (Ttimer_val * 0x10000) + remaining;
|
|
|
|
if ( Timer_driver_Find_average_overhead == 1 )
|
|
return total; /* in one-half microsecond units */
|
|
|
|
else {
|
|
if ( total < LEAST_VALID )
|
|
return 0; /* below timer resolution */
|
|
return (total-AVG_OVERHEAD) >> 1;
|
|
}
|
|
}
|
|
|
|
rtems_status_code Empty_function( void )
|
|
{
|
|
return RTEMS_SUCCESSFUL;
|
|
}
|
|
|
|
void Set_find_average_overhead(
|
|
rtems_boolean find_flag
|
|
)
|
|
{
|
|
Timer_driver_Find_average_overhead = find_flag;
|
|
}
|