tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Maxim/TARGET_MAX32610/sleep.c

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  33
  34 #include "sleep_api.h"
  35 #include "us_ticker_api.h"
  36 #include "cmsis.h"
  37 #include "pwrman_regs.h"
  38 #include "pwrseq_regs.h"
  39 #include "ioman_regs.h"
  40 #include "rtc_regs.h"
  41
  42 #define MIN_DEEP_SLEEP_US       500
  43
  44 uint64_t rtc_read_us(void);
  45 void rtc_set_wakeup(uint64_t wakeupUs);
  46 void us_ticker_deinit(void);
  47 void us_ticker_set(timestamp_t timestamp);
  48
  49 static mxc_uart_regs_t *stdio_uart = (mxc_uart_regs_t*)STDIO_UART;
  50
  51 // Normal wait mode
  52 void sleep(void)
  53 {
  54     // Normal sleep mode for ARM core
  55     SCB->SCR = 0;
  56
  57     __DSB();
  58     __WFI();
  59 }
  60
  61 // Work-around for issue of clearing power sequencer I/O flag
  62 static void clearAllGPIOWUD(void)
  63 {
  64     uint32_t wud_req0 = MXC_IOMAN->wud_req0;
  65     uint32_t wud_req1 = MXC_IOMAN->wud_req1;
  66
  67     // I/O must be a wakeup detect to clear
  68     MXC_IOMAN->wud_req0 = 0xffffffff;
  69     MXC_IOMAN->wud_req1 = 0xffffffff;
  70
  71     // Clear all WUDs
  72     MXC_PWRMAN->wud_ctrl = (MXC_E_PWRMAN_PAD_MODE_CLEAR_SET << MXC_F_PWRMAN_WUD_CTRL_PAD_MODE_POS) | MXC_F_PWRMAN_WUD_CTRL_CLEAR_ALL;
  73     MXC_PWRMAN->wud_pulse0 = 1;
  74
  75     // Restore WUD requests
  76     MXC_IOMAN->wud_req0 = wud_req0;
  77     MXC_IOMAN->wud_req1 = wud_req1;
  78 }
  79
  80 // Low-power stop mode
  81 void deepsleep(void)
  82 {
  83     uint64_t sleepStartRtcUs;
  84     uint32_t sleepStartTickerUs;
  85     int32_t sleepDurationUs;
  86     uint64_t sleepEndRtcUs;
  87     uint64_t elapsedUs;
  88
  89     __disable_irq();
  90
  91     // Wait for all STDIO characters to be sent. The UART clock will stop.
  92     while (stdio_uart->status & MXC_F_UART_STATUS_TX_BUSY);
  93
  94     // Record the current times
  95     sleepStartRtcUs = rtc_read_us();
  96     sleepStartTickerUs = us_ticker_read();
  97
  98     // Get the next mbed timer expiration
  99     timestamp_t next_event = 0;
 100     us_ticker_get_next_timestamp(&next_event);
 101     sleepDurationUs = next_event - sleepStartTickerUs;
 102
 103     if (sleepDurationUs < MIN_DEEP_SLEEP_US) {
 104         /* The next wakeup is too soon. */
 105         __enable_irq();
 106         return;
 107     }
 108
 109     // Disable the us_ticker. It won't be clocked in DeepSleep
 110     us_ticker_deinit();
 111
 112     // Prepare to wakeup from the RTC
 113     rtc_set_wakeup(sleepStartRtcUs + sleepDurationUs);
 114
 115     // Prepare for LP1
 116     uint32_t reg0 = MXC_PWRSEQ->reg0;
 117     reg0 &= ~MXC_F_PWRSEQ_REG0_PWR_SVM3EN_SLP;  // disable VDD3 SVM during sleep mode
 118     reg0 &= ~MXC_F_PWRSEQ_REG0_PWR_SVM1EN_SLP;  // disable VREG18 SVM during sleep mode
 119     if (reg0 & MXC_F_PWRSEQ_REG0_PWR_RTCEN_RUN) {   // if real-time clock enabled during run
 120         reg0 |= MXC_F_PWRSEQ_REG0_PWR_RTCEN_SLP;    // enable real-time clock during sleep mode
 121     } else {
 122         reg0 &= ~MXC_F_PWRSEQ_REG0_PWR_RTCEN_SLP;   // disable real-time clock during sleep mode
 123     }
 124     reg0 |= MXC_F_PWRSEQ_REG0_PWR_CHZYEN_SLP;   // enable CHZY regulator during sleep mode
 125     reg0 |= MXC_F_PWRSEQ_REG0_PWR_LP1;          // go into LP1
 126     reg0 &= ~MXC_F_PWRSEQ_REG0_PWR_FIRST_BOOT;  // clear first boot flag
 127     MXC_PWRSEQ->reg0 = reg0;
 128
 129     MXC_PWRSEQ->reg3 = (MXC_PWRSEQ->reg3 & ~MXC_F_PWRSEQ_REG3_PWR_ROSEL_QUICK) | (3 << MXC_F_PWRSEQ_REG3_PWR_ROSEL_QUICK_POS);
 130
 131     // Deep sleep for ARM core
 132     SCB->SCR = SCB_SCR_SLEEPDEEP_Msk;
 133
 134     // clear latches for wakeup detect
 135     MXC_PWRSEQ->flags = MXC_PWRSEQ->flags;
 136     if (MXC_PWRSEQ->flags & MXC_F_PWRSEQ_FLAGS_PWR_IO_WAKEUP) {
 137         // attempt work-around for I/O flag clearing issue
 138         clearAllGPIOWUD();
 139         MXC_PWRSEQ->flags = MXC_F_PWRSEQ_FLAGS_PWR_IO_WAKEUP;
 140     }
 141
 142     // Wait for pending RTC transaction
 143     while (MXC_RTCTMR->ctrl & MXC_F_RTC_CTRL_PENDING);
 144
 145     // Ensure that the event register is clear
 146     __SEV();    // set event
 147     __WFE();    // clear event
 148
 149     // Enter LP1
 150     __WFE();
 151     // Woke up from LP1
 152
 153     // The RTC timer does not update until the next tick
 154     uint64_t tempUs = rtc_read_us();
 155     do {
 156         sleepEndRtcUs = rtc_read_us();
 157     } while(sleepEndRtcUs == tempUs);
 158
 159     // Get the elapsed time from the RTC. Wakeup could have been from some other event.
 160     elapsedUs = sleepEndRtcUs - sleepStartRtcUs;
 161
 162     // Update the us_ticker. It was not clocked during DeepSleep
 163     us_ticker_init();
 164     us_ticker_set(sleepStartTickerUs + elapsedUs);
 165     us_ticker_get_next_timestamp(&next_event);
 166     us_ticker_set_interrupt(next_event);
 167
 168     __enable_irq();
 169 }