mirror of
https://github.com/micropython/micropython.git
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Damien George
1b2f6e3d1f
Currently the mimxrt port has a resolution of only 1 second for `machine.RTC().datetime()` and `time.time_ns()`. This means (among other things) that it fails the `tests/extmod/time_time_ns.py` test, which requires requires at least 5ms of resolution. The underlying RTC hardware is just a 64-bit counter, and the HAL functions `SNVS_LP_SRTC_GetDatetime()` and `SNVS_LP_SRTC_SetDatetime()` do conversions between y/m/d/h/m/s and this 64-bit value, which counts at a rate of 32kHz. This commit changes the RTC code to access the 64-bit counter directly and therefore improve resolution of all RTC functions to 1/32768 seconds. That makes things much simpler because it a lot of places the code wants to know the number of seconds since the Epoch. Currently it uses a combination of `SNVS_LP_SRTC_GetDatetime()` and `timeutils_seconds_since_epoch()` which converts the 64-bit counter to date-time and then back to seconds. Those operations are computationally expensive. With this commit, getting the number of seconds since the Epoch is as simple as reading the 64-bit counter and dividing by 32768. We can leverage a lot of the timeutils functions to simplify everything, and make it similar to other ports like rp2. Benefits of this change: - simpler, more efficient code to get/set RTC - `machine.RTC().datetime()` now has a non-zero value in the last slot, being the number of microseconds, and has a resolution of 1/32768 seconds - `time.time_ns()` now has a resolution of 1/32768 seconds - the `test/extmod/time_time_ns.py` test now passes Signed-off-by: Damien George <damien@micropython.org>
51 lines
2.0 KiB
C
51 lines
2.0 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2021 Damien P. George
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* Copyright (c) 2021 Robert Hammelrath
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef MICROPY_INCLUDED_MIMXRT_MODMACHINE_H
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#define MICROPY_INCLUDED_MIMXRT_MODMACHINE_H
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#include "py/obj.h"
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extern const mp_obj_type_t machine_sdcard_type;
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void machine_adc_init(void);
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void machine_pin_irq_deinit(void);
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void machine_rtc_irq_deinit(void);
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void machine_pwm_deinit_all(void);
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void machine_uart_deinit_all(void);
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void machine_timer_init_PIT(void);
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void machine_sdcard_init0(void);
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void mimxrt_sdram_init(void);
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void machine_i2s_init0();
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void machine_i2s_deinit_all(void);
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void machine_rtc_start(void);
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uint64_t machine_rtc_get_ticks(void);
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uint64_t machine_rtc_get_seconds(void);
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void machine_rtc_alarm_helper(int seconds, bool repeat);
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void machine_uart_set_baudrate(mp_obj_t uart, uint32_t baudrate);
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#endif // MICROPY_INCLUDED_MIMXRT_MODMACHINE_H
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