Implement DELAY_NS with CYCCNT on Cortex-M7 (#12283)

2.0.x
Nils Hasenbanck 6 years ago committed by Scott Lahteine
parent f5498168ae
commit cafabf2055

@ -30,6 +30,7 @@
#include "HAL.h"
#include "../../inc/MarlinConfig.h"
#include "../shared/Delay.h"
#if ENABLED(EEPROM_EMULATED_WITH_SRAM)
#if STM32F7xx
@ -80,6 +81,11 @@ uint16_t HAL_adc_result;
// HAL initialization task
void HAL_init(void) {
// Needed for DELAY_NS() / DELAY_US() on CORTEX-M7
#if (defined(__arm__) || defined(__thumb__)) && __CORTEX_M == 7
enableCycleCounter();
#endif
FastIO_init();
#if ENABLED(SDSUPPORT)

@ -153,8 +153,6 @@ extern uint16_t HAL_adc_result;
// Public functions
// --------------------------------------------------------------------------
// Memory related
#define __bss_end __bss_end__

@ -26,7 +26,7 @@
#ifdef __MK20DX256__
#include "HAL.h"
#include "../Delay.h"
#include "../shared/Delay.h"
#include <Wire.h>

@ -19,6 +19,7 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#pragma once
/**
* Busy wait delay cycles routines:
@ -28,13 +29,35 @@
* DELAY_US(count): Delay execution in microseconds
*/
#ifndef MARLIN_DELAY_H
#define MARLIN_DELAY_H
#include "../../core/macros.h"
#include "../../core/millis_t.h"
#if defined(__arm__) || defined(__thumb__)
#if __CORTEX_M == 7
// Cortex-M7 can use the cycle counter of the DWT unit
// http://www.anthonyvh.com/2017/05/18/cortex_m-cycle_counter/
FORCE_INLINE static void enableCycleCounter() {
CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk;
// Unlock DWT.
DWT->LAR = 0xC5ACCE55;
DWT->CYCCNT = 0;
DWT->CTRL |= DWT_CTRL_CYCCNTENA_Msk;
}
FORCE_INLINE volatile uint32_t getCycleCount() { return DWT->CYCCNT; }
FORCE_INLINE static void DELAY_CYCLES(const uint32_t x) {
const uint32_t endCycles = getCycleCount() + x;
while (PENDING(getCycleCount(), endCycles)) { }
}
#else
// https://blueprints.launchpad.net/gcc-arm-embedded/+spec/delay-cycles
#define nop() __asm__ __volatile__("nop;\n\t":::)
@ -80,6 +103,8 @@
}
#undef nop
#endif
#elif defined(__AVR__)
#define nop() __asm__ __volatile__("nop;\n\t":::)
@ -144,5 +169,3 @@
// Delay in microseconds
#define DELAY_US(x) DELAY_CYCLES( (x) * (F_CPU / 1000000UL) )
#endif // MARLIN_DELAY_H

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