Zoltan Hudak / mbedPi

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source/BCM2835.cpp@2:131555dc6fb7, 2022-12-20 (annotated)

Committer:
hudakz
Date:
Tue Dec 20 12:16:18 2022 +0000
Revision:
2:131555dc6fb7
Parent:
1:1f2d9982fa8c 
Mbed API for Raspberry Pi boards equipped with BCM2836 SoC.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hudakz 1:1f2d9982fa8c 1 #include "BCM2835.h"
hudakz 1:1f2d9982fa8c 2
hudakz 1:1f2d9982fa8c 3 extern volatile uint32_t* bcm2835_st;
hudakz 1:1f2d9982fa8c 4 extern volatile timeval start_program;
hudakz 1:1f2d9982fa8c 5
hudakz 1:1f2d9982fa8c 6 /**
hudakz 1:1f2d9982fa8c 7 * @brief Reads the System Timer Counter (64-bits)
hudakz 1:1f2d9982fa8c 8 * @note
hudakz 1:1f2d9982fa8c 9 * @param
hudakz 1:1f2d9982fa8c 10 * @retval
hudakz 1:1f2d9982fa8c 11 */
hudakz 1:1f2d9982fa8c 12 uint64_t bcm2835_systimer_read(void)
hudakz 1:1f2d9982fa8c 13 {
hudakz 1:1f2d9982fa8c 14 volatile uint32_t* paddr;
hudakz 1:1f2d9982fa8c 15 uint32_t hi, lo;
hudakz 1:1f2d9982fa8c 16 uint64_t st;
hudakz 1:1f2d9982fa8c 17
hudakz 1:1f2d9982fa8c 18 if (bcm2835_st==MAP_FAILED) {
hudakz 1:1f2d9982fa8c 19 return 0;
hudakz 1:1f2d9982fa8c 20 }
hudakz 1:1f2d9982fa8c 21
hudakz 1:1f2d9982fa8c 22 paddr = bcm2835_st + BCM2835_ST_CHI/4;
hudakz 1:1f2d9982fa8c 23 hi = bcm2835_peri_read(paddr);
hudakz 1:1f2d9982fa8c 24
hudakz 1:1f2d9982fa8c 25 paddr = bcm2835_st + BCM2835_ST_CLO/4;
hudakz 1:1f2d9982fa8c 26 lo = bcm2835_peri_read(paddr);
hudakz 1:1f2d9982fa8c 27
hudakz 1:1f2d9982fa8c 28 paddr = bcm2835_st + BCM2835_ST_CHI/4;
hudakz 1:1f2d9982fa8c 29 st = bcm2835_peri_read(paddr);
hudakz 1:1f2d9982fa8c 30
hudakz 1:1f2d9982fa8c 31 /* Test for overflow */
hudakz 1:1f2d9982fa8c 32 if (st == hi)
hudakz 1:1f2d9982fa8c 33 {
hudakz 1:1f2d9982fa8c 34 st <<= 32;
hudakz 1:1f2d9982fa8c 35 st += lo;
hudakz 1:1f2d9982fa8c 36 }
hudakz 1:1f2d9982fa8c 37 else
hudakz 1:1f2d9982fa8c 38 {
hudakz 1:1f2d9982fa8c 39 st <<= 32;
hudakz 1:1f2d9982fa8c 40 paddr = bcm2835_st + BCM2835_ST_CLO/4;
hudakz 1:1f2d9982fa8c 41 st += bcm2835_peri_read(paddr);
hudakz 1:1f2d9982fa8c 42 }
hudakz 1:1f2d9982fa8c 43 return st;
hudakz 1:1f2d9982fa8c 44 }
hudakz 1:1f2d9982fa8c 45
hudakz 1:1f2d9982fa8c 46 /**
hudakz 1:1f2d9982fa8c 47 * @brief
hudakz 1:1f2d9982fa8c 48 * @note
hudakz 1:1f2d9982fa8c 49 * @param
hudakz 1:1f2d9982fa8c 50 * @retval
hudakz 1:1f2d9982fa8c 51 */
hudakz 1:1f2d9982fa8c 52 uint64_t us_ticker_read()
hudakz 1:1f2d9982fa8c 53 {
hudakz 1:1f2d9982fa8c 54 struct timeval end_point;
hudakz 1:1f2d9982fa8c 55 uint64_t elapsedTime;
hudakz 1:1f2d9982fa8c 56
hudakz 1:1f2d9982fa8c 57 // stop timer
hudakz 1:1f2d9982fa8c 58
hudakz 1:1f2d9982fa8c 59 gettimeofday(&end_point, NULL);
hudakz 1:1f2d9982fa8c 60
hudakz 1:1f2d9982fa8c 61 // compute and print the elapsed time in microseconds
hudakz 1:1f2d9982fa8c 62 //elapsedTime = (end_point.tv_sec - start_program.tv_sec) * 1000000.0; // sec to us
hudakz 1:1f2d9982fa8c 63 elapsedTime += (end_point.tv_usec - start_program.tv_usec);
hudakz 1:1f2d9982fa8c 64 return elapsedTime;
hudakz 1:1f2d9982fa8c 65 }
hudakz 1:1f2d9982fa8c 66
hudakz 1:1f2d9982fa8c 67 /**
hudakz 1:1f2d9982fa8c 68 * @brief
hudakz 1:1f2d9982fa8c 69 * @note
hudakz 1:1f2d9982fa8c 70 * @param
hudakz 1:1f2d9982fa8c 71 * @retval
hudakz 1:1f2d9982fa8c 72 */
hudakz 1:1f2d9982fa8c 73 void bcm2835_sleep_for_ms(unsigned int millis)
hudakz 1:1f2d9982fa8c 74 {
hudakz 1:1f2d9982fa8c 75 struct timespec sleeper;
hudakz 1:1f2d9982fa8c 76
hudakz 1:1f2d9982fa8c 77 sleeper.tv_sec = (time_t) (millis / 1000);
hudakz 1:1f2d9982fa8c 78 sleeper.tv_nsec = (long)(millis % 1000) * 1000000;
hudakz 1:1f2d9982fa8c 79 nanosleep(&sleeper, NULL);
hudakz 1:1f2d9982fa8c 80 }