34 lines
769 B
C
34 lines
769 B
C
#include <stdio.h>
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#include "AT91SAM7S256.h"
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#include "at91_sysc.h"
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#include "board.h"
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static void rtt_isr(uint32_t status)
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{
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*AT91C_RTTC_RTAR = *AT91C_RTTC_RTVR +1;
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static uint32_t i;
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*AT91C_PIOA_SODR = i;
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i = i ^ LED_ORANGE;
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*AT91C_PIOA_CODR = i;
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}
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void at91_rttc_test_init(void)
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{
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/* calculate SLOWCK from MAINCK and measured MAINF */
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uint32_t prescaler = MAINCK * 16 / (*AT91C_CKGR_MCFR & AT91C_CKGR_MAINF);
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sysc_register_isr(AT91_SYSIRQ_RTT, &rtt_isr);
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/*
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* AT91C_RTTC_RTTINCIEN doesn't work
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* use AT91C_RTTC_ALMIEN and increment RTAR in isr
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*/
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*AT91C_RTTC_RTAR = *AT91C_RTTC_RTVR +1;
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*AT91C_RTTC_RTMR = (AT91C_RTTC_RTPRES & prescaler) |
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AT91C_RTTC_ALMIEN |
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AT91C_RTTC_RTTRST;
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printf("rttc running at %ld Hz\n\r", prescaler);
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}
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