mcu.c

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/**
 * @file    mcu.c
 * @author  foxBMS Team
 * @date    2019-02-19 (date of creation)
 * @updated 2021-11-08 (date of last update)
 * @ingroup DRIVERS
 * @prefix  MCU
 *
 * @brief   Driver for the MCU module.
 *
 */
 
/*========== Includes =======================================================*/
#include "mcu.h"
 
#include "HL_system.h"
 
/*========== Macros and Definitions =========================================*/
 
/** This is defined in port.c for FreeRTOS.
 * It is named portRTI_CNT0_CPUC0_REG
 * This must be changed to reflect the FreeRTOS configuration
 */
#define MCU_RTI_CNT0_CPUC0_REG (0x00000001U)
 
/** threshold in order to limit the time spent in wait to avoid livelock in wait */
#define MCU_US_WAIT_TIMEOUT (10000U)
 
/*========== Static Constant and Variable Definitions =======================*/
 
/*========== Extern Constant and Variable Definitions =======================*/
 
/*========== Static Function Prototypes =====================================*/
 
/*========== Static Function Implementations ================================*/
 
/*========== Extern Function Implementations ================================*/
 
void MCU_delay_us(uint32_t delay_us) {
    uint32_t timeOut           = 0;
    uint32_t startValue        = 0;
    uint32_t rti_clock         = 0;
    uint32_t rti_nrOfCounts_us = 0;
 
    /**
     * This is the frequency of the FRC0 counter
     * data sheet SPNU563A-March 2018 p. 585 formula 23
     */
    rti_clock = (uint32_t)((AVCLK1_FREQ)*1000000.0f) / ((MCU_RTI_CNT0_CPUC0_REG) + 1u);
 
    /**
     * First the time of one FRC0 increment in microseconds is computed with
     * increment_time = (1/rti_clock)*1e6
     * The 1e6 factor is to get the period in microseconds.
     *
     * The number of increments needed to reach 1 microsecond is then
     * computed with
     * nr_increments_for_1us = (1us/increment_time)
     *
     * To avoid floating point computation problems, the number of
     * increments needed to reach 1 microsecond is computed at once with:
     */
    rti_nrOfCounts_us = (uint32_t)(((float)rti_clock) / 1e6f);
 
    /* Get current value of FRC0 counter */
    startValue = (uint32_t)MCU_RTI_CNT0_FRC0_REG;
 
    while (timeOut < MCU_US_WAIT_TIMEOUT) {
        /**
         * Poll FRC0 value until the value corresponding to the desired
         * waiting timing has been reached.
         * The timeout is to ensure the code does not get trapped here.
         */
        if (((uint32_t)MCU_RTI_CNT0_FRC0_REG - startValue) >= (delay_us * rti_nrOfCounts_us)) {
            break;
        }
        timeOut++;
    }
}
 
/*========== Externalized Static Function Implementations (Unit Test) =======*/