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authorJoel Sherrill <joel.sherrill@OARcorp.com>1996-10-15 20:57:04 +0000
committerJoel Sherrill <joel.sherrill@OARcorp.com>1996-10-15 20:57:04 +0000
commit752cd8fb98f1c65b9f482bdbebeef0bd14d98856 (patch)
tree0defcc0e4f536c41e46d2d8e4dc5d34e25900cf4 /c/src/lib/libbsp/i386/i386ex/timer
parentpatches to erc32.h to correct handling of timer mirror from Jiri Gaisler. (diff)
downloadrtems-752cd8fb98f1c65b9f482bdbebeef0bd14d98856.tar.bz2
initial version from Erik
Diffstat (limited to 'c/src/lib/libbsp/i386/i386ex/timer')
-rw-r--r--c/src/lib/libbsp/i386/i386ex/timer/timer.c99
-rw-r--r--c/src/lib/libbsp/i386/i386ex/timer/timerisr.s34
2 files changed, 133 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/i386/i386ex/timer/timer.c b/c/src/lib/libbsp/i386/i386ex/timer/timer.c
new file mode 100644
index 0000000000..3dbbd657c5
--- /dev/null
+++ b/c/src/lib/libbsp/i386/i386ex/timer/timer.c
@@ -0,0 +1,99 @@
+/* Timer_init()
+ *
+ * This routine initializes the timer on the FORCE CPU-386 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, 1990, 1991, 1992, 1993, 1994.
+ * On-Line Applications Research Corporation (OAR).
+ * All rights assigned to U.S. Government, 1994.
+ *
+ * This material may be reproduced by or for the U.S. Government pursuant
+ * to the copyright license under the clause at DFARS 252.227-7013. This
+ * notice must appear in all copies of this file and its derivatives.
+ *
+ * $Id$
+ */
+
+
+#include <rtems.h>
+#include <bsp.h>
+
+int Ttimer_val;
+rtems_boolean Timer_driver_Find_average_overhead;
+
+rtems_isr timerisr();
+
+#define TMR0 0xF040
+#define TMR1 0xF041
+#define TMR2 0xF042
+#define TMRCON 0xF043
+#define TMRCFG 0xF834
+
+void Timer_initialize()
+{
+
+ (void) set_vector( timerisr, 0x2a, 0 ); /* install ISR ( IR2 ) was 0x38*/
+
+ Ttimer_val = 0; /* clear timer ISR count */
+
+ outport_byte ( TMRCON , 0xb0 ); /* select tmr2, stay in mode 0 */
+ outport_byte ( TMR1 , 0xd2 ); /* set to 250 usec interval */
+ outport_byte ( TMR1 , 0x00 );
+ outport_byte ( TMRCON , 0x64 ); /* change to mode 2 ( starts timer ) */
+ /* interrupts ARE enabled */
+/* outport_byte( IERA, 0x41 ); enable interrupt */
+
+}
+
+#define AVG_OVERHEAD 3 /* It typically takes 3.0 microseconds */
+ /* (3 ticks) to start/stop the timer. */
+#define LEAST_VALID 4 /* Don't trust a value lower than this */
+
+int Read_timer()
+{
+ register rtems_unsigned32 clicks;
+ register rtems_unsigned32 total;
+
+/* outport_byte( TBCR, 0x00 ); stop the timer -- not needed on intel */
+
+ outport_byte ( TMRCON, 0x40 ); /* latch the count */
+ inport_byte ( TMR1, clicks ); /* read the count */
+
+ total = Ttimer_val + 250 - clicks;
+
+/* outport_byte( TBCR, 0x00 ); initial value */
+/* outport_byte( IERA, 0x40 ); disable interrupt */
+
+ /* ??? Is "do not restore old vector" causing problems? */
+
+ if ( Timer_driver_Find_average_overhead == 1 )
+ return total; /* in one microsecond units */
+
+ else {
+ if ( total < LEAST_VALID )
+ return 0; /* below timer resolution */
+ return (total - AVG_OVERHEAD);
+ }
+}
+
+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;
+}
diff --git a/c/src/lib/libbsp/i386/i386ex/timer/timerisr.s b/c/src/lib/libbsp/i386/i386ex/timer/timerisr.s
new file mode 100644
index 0000000000..bda3056ade
--- /dev/null
+++ b/c/src/lib/libbsp/i386/i386ex/timer/timerisr.s
@@ -0,0 +1,34 @@
+/* timer_isr()
+ *
+ * This routine provides the ISR for the Z8036 timer on the MVME136
+ * board. The timer is set up to generate an interrupt at maximum
+ * intervals.
+ *
+ * Input parameters: NONE
+ *
+ * Output parameters: NONE
+ *
+ * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.
+ * On-Line Applications Research Corporation (OAR).
+ * All rights assigned to U.S. Government, 1994.
+ *
+ * This material may be reproduced by or for the U.S. Government pursuant
+ * to the copyright license under the clause at DFARS 252.227-7013. This
+ * notice must appear in all copies of this file and its derivatives.
+ *
+ * $Id$
+ */
+
+#include "asm.h"
+
+ BEGIN_CODE
+
+ EXTERN (Ttimer_val)
+
+ PUBLIC (timerisr)
+SYM (timerisr):
+ addl $250, SYM (Ttimer_val) # another 250 microseconds
+ iret
+
+END_CODE
+END