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targets/TARGET_NUVOTON/TARGET_M451/us_ticker.c
- Committer:
- <>
- Date:
- 2017-03-14
- Revision:
- 160:d5399cc887bb
- Parent:
- 159:612c381a210f
File content as of revision 160:d5399cc887bb:
/* mbed Microcontroller Library * Copyright (c) 2015-2016 Nuvoton * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include "us_ticker_api.h" #include "sleep_api.h" #include "mbed_assert.h" #include "nu_modutil.h" #include "nu_miscutil.h" #include "mbed_critical.h" // us_ticker tick = us = timestamp #define US_PER_TICK 1 #define US_PER_SEC (1000 * 1000) #define TMR0HIRES_CLK_PER_SEC (1000 * 1000) #define TMR1HIRES_CLK_PER_SEC (1000 * 1000) #define US_PER_TMR0HIRES_CLK (US_PER_SEC / TMR0HIRES_CLK_PER_SEC) #define US_PER_TMR1HIRES_CLK (US_PER_SEC / TMR1HIRES_CLK_PER_SEC) #define US_PER_TMR0HIRES_INT (1000 * 1000 * 10) #define TMR0HIRES_CLK_PER_TMR0HIRES_INT ((uint32_t) ((uint64_t) US_PER_TMR0HIRES_INT * TMR0HIRES_CLK_PER_SEC / US_PER_SEC)) static void tmr0_vec(void); static void tmr1_vec(void); static void us_ticker_arm_cd(void); static int us_ticker_inited = 0; static volatile uint32_t counter_major = 0; static volatile uint32_t cd_major_minor_us = 0; static volatile uint32_t cd_minor_us = 0; // NOTE: PCLK is set up in mbed_sdk_init(), invocation of which must be before C++ global object constructor. See init_api.c for details. // NOTE: Choose clock source of timer: // 1. HIRC: Be the most accurate but might cause unknown HardFault. // 2. HXT: Less accurate and cannot pass mbed-drivers test. // 3. PCLK(HXT): Less accurate but can pass mbed-drivers test. // NOTE: TIMER_0 for normal counter, TIMER_1 for countdown. static const struct nu_modinit_s timer0hires_modinit = {TIMER_0, TMR0_MODULE, CLK_CLKSEL1_TMR0SEL_PCLK0, 0, TMR0_RST, TMR0_IRQn, (void *) tmr0_vec}; static const struct nu_modinit_s timer1hires_modinit = {TIMER_1, TMR1_MODULE, CLK_CLKSEL1_TMR1SEL_PCLK0, 0, TMR1_RST, TMR1_IRQn, (void *) tmr1_vec}; #define TMR_CMP_MIN 2 #define TMR_CMP_MAX 0xFFFFFFu void us_ticker_init(void) { if (us_ticker_inited) { return; } counter_major = 0; cd_major_minor_us = 0; cd_minor_us = 0; us_ticker_inited = 1; // Reset IP SYS_ResetModule(timer0hires_modinit.rsetidx); SYS_ResetModule(timer1hires_modinit.rsetidx); // Select IP clock source CLK_SetModuleClock(timer0hires_modinit.clkidx, timer0hires_modinit.clksrc, timer0hires_modinit.clkdiv); CLK_SetModuleClock(timer1hires_modinit.clkidx, timer1hires_modinit.clksrc, timer1hires_modinit.clkdiv); // Enable IP clock CLK_EnableModuleClock(timer0hires_modinit.clkidx); CLK_EnableModuleClock(timer1hires_modinit.clkidx); // Timer for normal counter uint32_t clk_timer0 = TIMER_GetModuleClock((TIMER_T *) NU_MODBASE(timer0hires_modinit.modname)); uint32_t prescale_timer0 = clk_timer0 / TMR0HIRES_CLK_PER_SEC - 1; MBED_ASSERT((prescale_timer0 != (uint32_t) -1) && prescale_timer0 <= 127); MBED_ASSERT((clk_timer0 % TMR0HIRES_CLK_PER_SEC) == 0); uint32_t cmp_timer0 = TMR0HIRES_CLK_PER_TMR0HIRES_INT; MBED_ASSERT(cmp_timer0 >= TMR_CMP_MIN && cmp_timer0 <= TMR_CMP_MAX); // NOTE: TIMER_CTL_CNTDATEN_Msk exists in NUC472, but not in M451. In M451, TIMER_CNT is updated continuously by default. ((TIMER_T *) NU_MODBASE(timer0hires_modinit.modname))->CTL = TIMER_PERIODIC_MODE | prescale_timer0/* | TIMER_CTL_CNTDATEN_Msk*/; ((TIMER_T *) NU_MODBASE(timer0hires_modinit.modname))->CMP = cmp_timer0; NVIC_SetVector(timer0hires_modinit.irq_n, (uint32_t) timer0hires_modinit.var); NVIC_SetVector(timer1hires_modinit.irq_n, (uint32_t) timer1hires_modinit.var); NVIC_EnableIRQ(timer0hires_modinit.irq_n); NVIC_EnableIRQ(timer1hires_modinit.irq_n); TIMER_EnableInt((TIMER_T *) NU_MODBASE(timer0hires_modinit.modname)); TIMER_Start((TIMER_T *) NU_MODBASE(timer0hires_modinit.modname)); } uint32_t us_ticker_read() { if (! us_ticker_inited) { us_ticker_init(); } TIMER_T * timer0_base = (TIMER_T *) NU_MODBASE(timer0hires_modinit.modname); do { uint32_t major_minor_us; uint32_t minor_us; // NOTE: As TIMER_CNT = TIMER_CMP and counter_major has increased by one, TIMER_CNT doesn't change to 0 for one tick time. // NOTE: As TIMER_CNT = TIMER_CMP or TIMER_CNT = 0, counter_major (ISR) may not sync with TIMER_CNT. So skip and fetch stable one at the cost of 1 clock delay on this read. do { core_util_critical_section_enter(); // NOTE: Order of reading minor_us/carry here is significant. minor_us = TIMER_GetCounter(timer0_base) * US_PER_TMR0HIRES_CLK; uint32_t carry = (timer0_base->INTSTS & TIMER_INTSTS_TIF_Msk) ? 1 : 0; // When TIMER_CNT approaches TIMER_CMP and will wrap soon, we may get carry but TIMER_CNT not wrapped. Hanlde carefully carry == 1 && TIMER_CNT is near TIMER_CMP. if (carry && minor_us > (US_PER_TMR0HIRES_INT / 2)) { major_minor_us = (counter_major + 1) * US_PER_TMR0HIRES_INT; } else { major_minor_us = (counter_major + carry) * US_PER_TMR0HIRES_INT + minor_us; } core_util_critical_section_exit(); } while (minor_us == 0 || minor_us == US_PER_TMR0HIRES_INT); return (major_minor_us / US_PER_TICK); } while (0); } void us_ticker_disable_interrupt(void) { TIMER_DisableInt((TIMER_T *) NU_MODBASE(timer1hires_modinit.modname)); } void us_ticker_clear_interrupt(void) { TIMER_ClearIntFlag((TIMER_T *) NU_MODBASE(timer1hires_modinit.modname)); } void us_ticker_set_interrupt(timestamp_t timestamp) { TIMER_Stop((TIMER_T *) NU_MODBASE(timer1hires_modinit.modname)); int delta = (int) (timestamp - us_ticker_read()); if (delta > 0) { cd_major_minor_us = delta * US_PER_TICK; us_ticker_arm_cd(); } else { cd_major_minor_us = cd_minor_us = 0; /** * This event was in the past. Set the interrupt as pending, but don't process it here. * This prevents a recurive loop under heavy load which can lead to a stack overflow. */ NVIC_SetPendingIRQ(timer1hires_modinit.irq_n); } } static void tmr0_vec(void) { TIMER_ClearIntFlag((TIMER_T *) NU_MODBASE(timer0hires_modinit.modname)); counter_major ++; } static void tmr1_vec(void) { TIMER_ClearIntFlag((TIMER_T *) NU_MODBASE(timer1hires_modinit.modname)); cd_major_minor_us = (cd_major_minor_us > cd_minor_us) ? (cd_major_minor_us - cd_minor_us) : 0; if (cd_major_minor_us == 0) { // NOTE: us_ticker_set_interrupt() may get called in us_ticker_irq_handler(); us_ticker_irq_handler(); } else { us_ticker_arm_cd(); } } static void us_ticker_arm_cd(void) { TIMER_T * timer1_base = (TIMER_T *) NU_MODBASE(timer1hires_modinit.modname); cd_minor_us = cd_major_minor_us; // Reset 8-bit PSC counter, 24-bit up counter value and CNTEN bit timer1_base->CTL |= TIMER_CTL_RSTCNT_Msk; // One-shot mode, Clock = 1 MHz uint32_t clk_timer1 = TIMER_GetModuleClock((TIMER_T *) NU_MODBASE(timer1hires_modinit.modname)); uint32_t prescale_timer1 = clk_timer1 / TMR1HIRES_CLK_PER_SEC - 1; MBED_ASSERT((prescale_timer1 != (uint32_t) -1) && prescale_timer1 <= 127); MBED_ASSERT((clk_timer1 % TMR1HIRES_CLK_PER_SEC) == 0); // NOTE: TIMER_CTL_CNTDATEN_Msk exists in NUC472, but not in M451. In M451, TIMER_CNT is updated continuously by default. timer1_base->CTL &= ~(TIMER_CTL_OPMODE_Msk | TIMER_CTL_PSC_Msk/* | TIMER_CTL_CNTDATEN_Msk*/); timer1_base->CTL |= TIMER_ONESHOT_MODE | prescale_timer1/* | TIMER_CTL_CNTDATEN_Msk*/; uint32_t cmp_timer1 = cd_minor_us / US_PER_TMR1HIRES_CLK; cmp_timer1 = NU_CLAMP(cmp_timer1, TMR_CMP_MIN, TMR_CMP_MAX); timer1_base->CMP = cmp_timer1; TIMER_EnableInt(timer1_base); TIMER_Start(timer1_base); }