diff options
Diffstat (limited to '')
| -rw-r--r-- | c/src/lib/libbsp/m68k/uC5282/clock/clock.c | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/m68k/uC5282/clock/clock.c b/c/src/lib/libbsp/m68k/uC5282/clock/clock.c new file mode 100644 index 0000000000..8b10dbfd28 --- /dev/null +++ b/c/src/lib/libbsp/m68k/uC5282/clock/clock.c @@ -0,0 +1,68 @@ +/* + * Use the last periodic interval timer (PIT3) as the system clock. + * + * $Id$ + */ + +#include <rtems.h> +#include <bsp.h> +#include <mcf5282/mcf5282.h> + +/* + * Use INTC0 base + */ +#define CLOCK_VECTOR (64+58) + +/* + * Periodic interval timer interrupt handler + */ +#define Clock_driver_support_at_tick() \ + do { \ + MCF5282_PIT3_PCSR |= MCF5282_PIT_PCSR_PIF; \ + } while (0) \ + +/* + * Attach clock interrupt handler + */ +#define Clock_driver_support_install_isr( _new, _old ) \ + do { \ + _old = (rtems_isr_entry)set_vector(_new, CLOCK_VECTOR, 1); \ + } while(0) + +/* + * Turn off the clock + */ +#define Clock_driver_support_shutdown_hardware() \ + do { \ + MCF5282_PIT3_PCSR &= ~MCF5282_PIT_PCSR_EN; \ + } while(0) + +/* + * Set up the clock hardware + * + * Prescale so that it counts in microseconds + * System clock frequency better be 2**n (1<=n<=16) MHz! + */ +#define Clock_driver_support_initialize_hardware() \ + do { \ + int level; \ + int preScaleCode = -2; \ + int preScaleDivisor = get_CPU_clock_speed() / 1000000; \ + while (preScaleDivisor) { \ + preScaleDivisor >>= 1; \ + preScaleCode++; \ + } \ + MCF5282_INTC0_ICR58 = MCF5282_INTC_ICR_IL(PIT3_IRQ_LEVEL) | \ + MCF5282_INTC_ICR_IP(PIT3_IRQ_PRIORITY); \ + rtems_interrupt_disable( level ); \ + MCF5282_INTC0_IMRH &= ~MCF5282_INTC_IMRH_INT58; \ + MCF5282_PIT3_PCSR &= ~MCF5282_PIT_PCSR_EN; \ + rtems_interrupt_enable( level ); \ + MCF5282_PIT3_PMR = BSP_Configuration.microseconds_per_tick - 1; \ + MCF5282_PIT3_PCSR = MCF5282_PIT_PCSR_PRE(preScaleCode) | \ + MCF5282_PIT_PCSR_PIE | \ + MCF5282_PIT_PCSR_RLD | \ + MCF5282_PIT_PCSR_EN; \ + } while (0) + +#include "../../../shared/clockdrv_shell.c" |