diff options
| author | Clyne Sullivan <tullivan99@gmail.com> | 2019-02-28 17:04:22 -0500 |
|---|---|---|
| committer | Clyne Sullivan <tullivan99@gmail.com> | 2019-02-28 17:04:22 -0500 |
| commit | d6869d1ec4bd24cd2c3eafa534f0849b25ec5607 (patch) | |
| tree | 79e54ed27b39c31864895535d11399708d5a45c0 /arduino/cores/nRF5/delay.h | |
| parent | 614ee97bf3a2270c413527a7f35c54cbecd9e601 (diff) | |
added basic code
Diffstat (limited to 'arduino/cores/nRF5/delay.h')
| -rwxr-xr-x | arduino/cores/nRF5/delay.h | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/arduino/cores/nRF5/delay.h b/arduino/cores/nRF5/delay.h new file mode 100755 index 0000000..f25809f --- /dev/null +++ b/arduino/cores/nRF5/delay.h @@ -0,0 +1,105 @@ +/* + Copyright (c) 2015 Arduino LLC. All right reserved. + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +*/ + +#ifndef _DELAY_ +#define _DELAY_ + +#ifdef __cplusplus +extern "C" { +#endif + +#include <stdint.h> +#include "nrfx.h" +#include "variant.h" + +/** + * \brief Returns the number of milliseconds since the Arduino board began running the current program. + * + * This number will overflow (go back to zero), after approximately 50 days. + * + * \return Number of milliseconds since the program started (uint32_t) + */ +extern uint32_t millis( void ) ; + +/** + * \brief Returns the number of microseconds since the Arduino board began running the current program. + * + * This number will overflow (go back to zero), after approximately 70 minutes. On 16 MHz Arduino boards + * (e.g. Duemilanove and Nano), this function has a resolution of four microseconds (i.e. the value returned is + * always a multiple of four). On 8 MHz Arduino boards (e.g. the LilyPad), this function has a resolution + * of eight microseconds. + * + * \note There are 1,000 microseconds in a millisecond and 1,000,000 microseconds in a second. + */ +extern uint32_t micros( void ) ; + +/** + * \brief Pauses the program for the amount of time (in miliseconds) specified as parameter. + * (There are 1000 milliseconds in a second.) + * + * \param dwMs the number of milliseconds to pause (uint32_t) + */ +extern void delay( uint32_t dwMs ); + +/** + * \brief Pauses the program for the amount of time (in microseconds) specified as parameter. + * + * \param dwUs the number of microseconds to pause (uint32_t) + */ +static __inline__ void delayMicroseconds( uint32_t ) __attribute__((always_inline, unused)) ; +static __inline__ void delayMicroseconds( uint32_t usec ) +{ + nrfx_coredep_delay_us(usec); +} + +/** + * Enable DWT, required for delay_ns() + */ +void dwt_enable(void); +void dwt_disable(void); + + +/** + * Delay nano seconds, delay_ns() make use of DWT of debug core. + * dwt_enable() must be called previously. + * Note: nrf52 run at 64MHz + * - 1000 ns ~ 64 cycles + * - 500 ns ~ 32 cycles + * - 250 ns ~ 16 cycles + * - 125 ns ~ 8 cycles + */ +// Enable pragma when this bug is fixed https://bugs.launchpad.net/gcc-arm-embedded/+bug/1534360 +// #pragma GCC push_options +// #pragma GCC optimize ("Ofast") + +#define DELAY_CYCLE_CORRECTION 8 // ~125 ns overhead for delay_ns() +#define delay_ns(ns) \ + do {\ + register uint32_t _endtime = DWT->CYCCNT;\ + _endtime += ((F_CPU/1000000)*ns)/1000 - DELAY_CYCLE_CORRECTION;\ + while (DWT->CYCCNT < _endtime) {}\ + } while(0) + +// #pragma GCC pop_options + + +#ifdef __cplusplus +} +#endif + +#endif /* _DELAY_ */ |