diff options
Diffstat (limited to 'tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Maxim/TARGET_MAX32610/us_ticker.c')
| -rw-r--r-- | tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Maxim/TARGET_MAX32610/us_ticker.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Maxim/TARGET_MAX32610/us_ticker.c b/tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Maxim/TARGET_MAX32610/us_ticker.c new file mode 100644 index 0000000000..17690d5da4 --- /dev/null +++ b/tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Maxim/TARGET_MAX32610/us_ticker.c @@ -0,0 +1,261 @@ +/******************************************************************************* + * Copyright (C) 2015 Maxim Integrated Products, Inc., All Rights Reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included + * in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS + * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. + * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES + * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + * + * Except as contained in this notice, the name of Maxim Integrated + * Products, Inc. shall not be used except as stated in the Maxim Integrated + * Products, Inc. Branding Policy. + * + * The mere transfer of this software does not imply any licenses + * of trade secrets, proprietary technology, copyrights, patents, + * trademarks, maskwork rights, or any other form of intellectual + * property whatsoever. Maxim Integrated Products, Inc. retains all + * ownership rights. + ******************************************************************************* + */ + +#include "mbed_error.h" +#include "us_ticker_api.h" +#include "PeripheralNames.h" +#include "tmr_regs.h" + +#define US_TIMER MXC_TMR0 +#define US_TIMER_IRQn TMR0_IRQn + +static int us_ticker_inited = 0; +static uint32_t ticks_per_us; +static uint32_t tick_win; +static volatile uint64_t current_cnt; // Hold the current ticks +static volatile uint64_t event_cnt; // Holds the value of the next event + +#define ticks_to_us(ticks) ((ticks) / ticks_per_us); +#define MAX_TICK_VAL ((uint64_t)0xFFFFFFFF * ticks_per_us) + +//****************************************************************************** +static inline void inc_current_cnt(uint32_t inc) { + + // Overflow the ticker when the us ticker overflows + current_cnt += inc; + if(current_cnt > MAX_TICK_VAL) { + current_cnt -= (MAX_TICK_VAL + 1); + } +} + +//****************************************************************************** +static inline int event_passed(uint64_t current, uint64_t event) { + + // Determine if the event has already happened. + // If the event is behind the current ticker, within a window, + // then the event has already happened. + if(((current < tick_win) && ((event < current) || + (event > (MAX_TICK_VAL - (tick_win - current))))) || + ((event < current) && (event > (current - tick_win)))) { + return 1; + } + + return 0; +} + +//****************************************************************************** +static inline uint64_t event_diff(uint64_t current, uint64_t event) { + + // Check to see if the ticker will overflow before the event + if(current <= event) { + return (event - current); + } + + return ((MAX_TICK_VAL - current) + event); +} + +//****************************************************************************** +static void tmr_handler(void) +{ + uint32_t term_cnt32 = US_TIMER->term_cnt32; + US_TIMER->term_cnt32 = 0xFFFFFFFF; // reset to max value to prevent further interrupts + US_TIMER->intfl = (MXC_F_TMR_INTFL_TIMER0 | MXC_F_TMR_INTFL_TIMER1); // clear interrupt + NVIC_ClearPendingIRQ(US_TIMER_IRQn); + + inc_current_cnt(term_cnt32); + + if (event_passed(current_cnt + US_TIMER->count32, event_cnt )) { + // the timestamp has expired + event_cnt = 0xFFFFFFFFFFFFFFFFULL; // reset to max value + us_ticker_irq_handler(); + } else { + + uint64_t diff = event_diff(current_cnt, event_cnt); + if (diff < (uint64_t)0xFFFFFFFF) { + // the event occurs before the next overflow + US_TIMER->term_cnt32 = diff; + + // Since the timer keeps counting after the terminal value is reached, it is possible that the new + // terminal value is in the past. + if (US_TIMER->term_cnt32 < US_TIMER->count32) { + // the timestamp has expired + US_TIMER->term_cnt32 = 0xFFFFFFFF; // reset to max value to prevent further interrupts + US_TIMER->intfl = (MXC_F_TMR_INTFL_TIMER0 | MXC_F_TMR_INTFL_TIMER1); // clear interrupt + NVIC_ClearPendingIRQ(US_TIMER_IRQn); + event_cnt = 0xFFFFFFFFFFFFFFFFULL; // reset to max value + us_ticker_irq_handler(); + } + } + } +} + +//****************************************************************************** +void us_ticker_init(void) +{ + if (us_ticker_inited) + return; + us_ticker_inited = 1; + + current_cnt = 0; + event_cnt = 0xFFFFFFFFFFFFFFFFULL; // reset to max value + + if (SystemCoreClock <= 1000000) { + error("us_ticker cannot operate at this SystemCoreClock"); + return; + } + + // Configure timer for 32-bit continuous mode with /1 prescaler + US_TIMER->ctrl = MXC_E_TMR_MODE_CONTINUOUS << MXC_F_TMR_CTRL_MODE_POS | (0 << MXC_F_TMR_CTRL_PRESCALE_POS); + ticks_per_us = SystemCoreClock / 1000000; + + // Set the tick window to 10ms + tick_win = SystemCoreClock/100; + + // Set timer overflow to the max + US_TIMER->term_cnt32 = 0xFFFFFFFF; + US_TIMER->pwm_cap32 = 0xFFFFFFFF; + US_TIMER->count32 = 0; + + US_TIMER->intfl = (MXC_F_TMR_INTFL_TIMER0 | MXC_F_TMR_INTFL_TIMER1); // clear pending interrupts + + NVIC_SetVector(US_TIMER_IRQn, (uint32_t)tmr_handler); + NVIC_EnableIRQ(US_TIMER_IRQn); + + US_TIMER->inten |= MXC_F_TMR_INTEN_TIMER0; // enable interrupts + US_TIMER->ctrl |= MXC_F_TMR_CTRL_ENABLE0; // enable timer +} + +//****************************************************************************** +void us_ticker_deinit(void) +{ + US_TIMER->ctrl = 0; // disable timer + US_TIMER->inten = 0; // disable interrupts + US_TIMER->intfl = (MXC_F_TMR_INTFL_TIMER0 | MXC_F_TMR_INTFL_TIMER1); // clear interrupts + us_ticker_inited = 0; +} + +//****************************************************************************** +uint32_t us_ticker_read(void) +{ + uint64_t current_cnt1, current_cnt2; + uint32_t term_cnt, tmr_cnt; + int intfl1, intfl2; + + if (!us_ticker_inited) + us_ticker_init(); + + // Ensure coherency between current_cnt and US_TIMER->count32 + do { + current_cnt1 = current_cnt; + intfl1 = US_TIMER->intfl; + term_cnt = US_TIMER->term_cnt32; + tmr_cnt = US_TIMER->count32; + intfl2 = US_TIMER->intfl; + current_cnt2 = current_cnt; + } while ((current_cnt1 != current_cnt2) || (intfl1 != intfl2)); + + if (intfl1) { + current_cnt1 += term_cnt; + } + + current_cnt1 += tmr_cnt; + + return (current_cnt1 / ticks_per_us); +} + +//****************************************************************************** +void us_ticker_set_interrupt(timestamp_t timestamp) +{ + // Note: interrupts are disabled before this function is called. + US_TIMER->ctrl &= ~MXC_F_TMR_CTRL_ENABLE0; // disable timer + + if (US_TIMER->intfl) { + US_TIMER->intfl = (MXC_F_TMR_INTFL_TIMER0 | MXC_F_TMR_INTFL_TIMER1); // clear interrupt + NVIC_ClearPendingIRQ(US_TIMER_IRQn); + inc_current_cnt(US_TIMER->term_cnt32); + } + + // add and reset the current count value + inc_current_cnt(US_TIMER->count32); + US_TIMER->count32 = 0; + + // add the number of cycles that the timer is disabled here for + inc_current_cnt(200); + + event_cnt = (uint64_t)timestamp * ticks_per_us; + + // Check to see if the event has already passed + if (!event_passed(current_cnt, event_cnt)) { + uint64_t diff = event_diff(current_cnt, event_cnt); + if (diff < (uint64_t)0xFFFFFFFF) { + // the event occurs before the next overflow + US_TIMER->term_cnt32 = diff; + } else { + // the event occurs after the next overflow + US_TIMER->term_cnt32 = 0xFFFFFFFF; // set to max + } + } else { + // the requested timestamp occurs in the past + // set the timer up to immediately expire + US_TIMER->term_cnt32 = 1; + } + US_TIMER->ctrl |= MXC_F_TMR_CTRL_ENABLE0; // enable timer +} + +//****************************************************************************** +void us_ticker_disable_interrupt(void) +{ + // There are no more events, set timer overflow to the max + US_TIMER->term_cnt32 = 0xFFFFFFFF; +} + +//****************************************************************************** +void us_ticker_clear_interrupt(void) +{ + // cleared in the local handler +} + +//****************************************************************************** +void us_ticker_set(timestamp_t timestamp) +{ + US_TIMER->ctrl &= ~MXC_F_TMR_CTRL_ENABLE0; // disable timer + current_cnt = (uint64_t)timestamp * ticks_per_us; + US_TIMER->count32 = 0; + US_TIMER->term_cnt32 = 0xFFFFFFFF; + US_TIMER->ctrl |= MXC_F_TMR_CTRL_ENABLE0; // enable timer + + if (((uint64_t)timestamp * ticks_per_us) >= event_cnt) { + // The next timestamp has elapsed. Trigger the interrupt to handle it. + NVIC_SetPendingIRQ(US_TIMER_IRQn); + } +} |