Changeset 24697c3 in mainline

Timestamp:

2010-07-16T14:07:48Z (14 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

4d0f97d, ec08286

Parents:

dfd735a1

Message:

Program timer with the right frequency. (Expect HZ to be 100 Hz for now.)

File:

• kernel/arch/arm32/src/mach/gta02/gta02.c (modified) (2 diffs)

kernel/arch/arm32/src/mach/gta02/gta02.c

@@ -225 +225 @@
          */
 
-        /* Set prescaler values to zero. (no pre-divison), no dead zone. */
-        pio_write_32(&timer->tcfg0, 0);
+        /*
+         * GTA02 PCLK should be 100 MHz.
+         * Timer input freq. = PCLK / divider / (1+prescaler)
+         * 100 MHz / 2 / (1+7) / 62500 ~= 100 Hz
+         */
+#if HZ != 100
+#warning Other HZ than 100 not suppored.
+#endif
+
+        /* Set prescaler values. No pre-divison, no dead zone. */
+        pio_write_32(&timer->tcfg0, 7); /* prescale 1/8 */
 
         /* No DMA request, divider value = 2 for all timers. */
@@ -235 +244 @@
 
         /* Start counting from 64k-1. Compare value is irrelevant. */
-        pio_write_32(&timer->timer[0].cntb, 0xffff);
+        pio_write_32(&timer->timer[0].cntb, 62500);
         pio_write_32(&timer->timer[0].cmpb, 0);