mirror of https://github.com/ARMmbed/mbed-os.git
Merge branch 'nrf52_nrf51_unified_integration' of https://github.com/pan-/mbed into refactored_serial_api
# Conflicts: # hal/targets/hal/TARGET_NORDIC/TARGET_NRF5/sdk/drivers_nrf/uart/nrf_drv_uart.cpull/2261/head^2
Głąbek, Andrzej
commit
91bd396a08
|
|
@ -24,7 +24,7 @@
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// Instance 0 is reserved for SoftDevice.
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// Instance 1 is used as a common one for us_ticker, lp_ticker and (in case
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// of NRF51) as an alternative tick source for RTOS.
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// ["os_tick.c" uses hard coded addresses of the 'NRF_RTC1->EVENT_COMPARE[1]'
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// ["us_ticker.c" uses hard coded addresses of the 'NRF_RTC1->EVENT_COMPARE[1]'
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// register in inline assembly implementations of COMMON_RTC_IRQ_HANDLER,
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// please remember to update those in case of doing changes here]
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#define COMMON_RTC_INSTANCE NRF_RTC1
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|
|
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@ -1,379 +0,0 @@
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/*
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* Copyright (c) 2013 Nordic Semiconductor ASA
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* All rights reserved.
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||||
*
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||||
* Redistribution and use in source and binary forms, with or without modification,
|
||||
* are permitted provided that the following conditions are met:
|
||||
*
|
||||
* 1. Redistributions of source code must retain the above copyright notice, this list
|
||||
* of conditions and the following disclaimer.
|
||||
*
|
||||
* 2. Redistributions in binary form, except as embedded into a Nordic Semiconductor ASA
|
||||
* integrated circuit in a product or a software update for such product, must reproduce
|
||||
* the above copyright notice, this list of conditions and the following disclaimer in
|
||||
* the documentation and/or other materials provided with the distribution.
|
||||
*
|
||||
* 3. Neither the name of Nordic Semiconductor ASA nor the names of its contributors may be
|
||||
* used to endorse or promote products derived from this software without specific prior
|
||||
* written permission.
|
||||
*
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||||
* 4. This software, with or without modification, must only be used with a
|
||||
* Nordic Semiconductor ASA integrated circuit.
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||||
*
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||||
* 5. Any software provided in binary or object form under this license must not be reverse
|
||||
* engineered, decompiled, modified and/or disassembled.
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||||
*
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||||
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
|
||||
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
||||
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
||||
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
|
||||
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
||||
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
||||
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
|
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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||||
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#if defined(TARGET_MCU_NRF51822)
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#include "common_rtc.h"
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#include "toolchain.h"
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#include "nrf_drv_common.h"
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#define MAX_RTC_COUNTER_VAL ((1uL << RTC_COUNTER_BITS) - 1)
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/**
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* The value previously set in the capture compare register of channel 1
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*/
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static uint32_t previous_tick_cc_value = 0;
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/*
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RTX provide the following definitions which are used by the tick code:
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* os_trv: The number (minus 1) of clock cycle between two tick.
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* os_clockrate: Time duration between two ticks (in us).
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* OS_Tick_Handler: The function which handle a tick event.
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This function is special because it never returns.
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Those definitions are used by the code which handle the os tick.
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To allow compilation of us_ticker programs without RTOS, those symbols are
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exported from this module as weak ones.
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*/
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MBED_WEAK uint32_t const os_trv;
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MBED_WEAK uint32_t const os_clockrate;
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MBED_WEAK void OS_Tick_Handler() { }
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#if defined (__CC_ARM) /* ARMCC Compiler */
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__asm void COMMON_RTC_IRQ_HANDLER(void)
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{
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IMPORT OS_Tick_Handler
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IMPORT common_rtc_irq_handler
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/**
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* Chanel 1 of RTC1 is used by RTX as a systick.
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* If the compare event on channel 1 is set, then branch to OS_Tick_Handler.
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* Otherwise, just execute common_rtc_irq_handler.
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* This function has to be written in assembly and tagged as naked because OS_Tick_Handler
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* will never return.
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* A c function would put lr on the stack before calling OS_Tick_Handler and this value
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* would never been dequeued.
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*
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* \code
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* void COMMON_RTC_IRQ_HANDLER(void) {
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if(NRF_RTC1->EVENTS_COMPARE[1]) {
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// never return...
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OS_Tick_Handler();
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} else {
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common_rtc_irq_handler();
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}
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}
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* \endcode
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*/
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ldr r0,=0x40011144
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ldr r1, [r0, #0]
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cmp r1, #0
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beq US_TICKER_HANDLER
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bl OS_Tick_Handler
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US_TICKER_HANDLER
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push {r3, lr}
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bl common_rtc_irq_handler
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pop {r3, pc}
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nop /* padding */
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}
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#elif defined (__GNUC__) /* GNU Compiler */
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__attribute__((naked)) void COMMON_RTC_IRQ_HANDLER(void)
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{
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/**
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* Chanel 1 of RTC1 is used by RTX as a systick.
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* If the compare event on channel 1 is set, then branch to OS_Tick_Handler.
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* Otherwise, just execute common_rtc_irq_handler.
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* This function has to be written in assembly and tagged as naked because OS_Tick_Handler
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* will never return.
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* A c function would put lr on the stack before calling OS_Tick_Handler and this value
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* would never been dequeued.
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*
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* \code
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* void COMMON_RTC_IRQ_HANDLER(void) {
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if(NRF_RTC1->EVENTS_COMPARE[1]) {
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// never return...
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OS_Tick_Handler();
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} else {
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common_rtc_irq_handler();
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}
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}
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* \endcode
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*/
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__asm__ (
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"ldr r0,=0x40011144\n"
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"ldr r1, [r0, #0]\n"
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"cmp r1, #0\n"
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"beq US_TICKER_HANDLER\n"
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"bl OS_Tick_Handler\n"
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"US_TICKER_HANDLER:\n"
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"push {r3, lr}\n"
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"bl common_rtc_irq_handler\n"
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"pop {r3, pc}\n"
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"nop"
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);
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}
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#elif defined (__ICCARM__)//IAR
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void common_rtc_irq_handler(void);
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__stackless __task void COMMON_RTC_IRQ_HANDLER(void)
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{
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uint32_t temp;
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__asm volatile(
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" ldr %[temp], [%[reg2check]] \n"
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" cmp %[temp], #0 \n"
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" beq 1f \n"
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" bl.w OS_Tick_Handler \n"
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"1: \n"
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" push {r3, lr}\n"
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" blx %[rtc_irq] \n"
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" pop {r3, pc}\n"
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: /* Outputs */
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[temp] "=&r"(temp)
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: /* Inputs */
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[reg2check] "r"(0x40011144),
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[rtc_irq] "r"(common_rtc_irq_handler)
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: /* Clobbers */
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"cc"
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);
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(void)temp;
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}
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#else
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#error Compiler not supported.
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#error Provide a definition of COMMON_RTC_IRQ_HANDLER.
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/*
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* Chanel 1 of RTC1 is used by RTX as a systick.
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* If the compare event on channel 1 is set, then branch to OS_Tick_Handler.
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* Otherwise, just execute common_rtc_irq_handler.
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* This function has to be written in assembly and tagged as naked because OS_Tick_Handler
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* will never return.
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* A c function would put lr on the stack before calling OS_Tick_Handler and this value
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* will never been dequeued. After a certain time a stack overflow will happen.
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*
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* \code
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* void COMMON_RTC_IRQ_HANDLER(void) {
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if(NRF_RTC1->EVENTS_COMPARE[1]) {
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// never return...
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OS_Tick_Handler();
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} else {
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common_rtc_irq_handler();
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}
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}
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* \endcode
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*/
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#endif
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/**
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* Return the next number of clock cycle needed for the next tick.
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* @note This function has been carrefuly optimized for a systick occuring every 1000us.
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*/
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static uint32_t get_next_tick_cc_delta() {
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uint32_t delta = 0;
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if (os_clockrate != 1000) {
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// In RTX, by default SYSTICK is is used.
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// A tick event is generated every os_trv + 1 clock cycles of the system timer.
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delta = os_trv + 1;
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} else {
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// If the clockrate is set to 1000us then 1000 tick should happen every second.
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// Unfortunatelly, when clockrate is set to 1000, os_trv is equal to 31.
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// If (os_trv + 1) is used as the delta value between two ticks, 1000 ticks will be
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// generated in 32000 clock cycle instead of 32768 clock cycles.
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// As a result, if a user schedule an OS timer to start in 100s, the timer will start
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// instead after 97.656s
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// The code below fix this issue, a clock rate of 1000s will generate 1000 ticks in 32768
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// clock cycles.
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// The strategy is simple, for 1000 ticks:
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// * 768 ticks will occur 33 clock cycles after the previous tick
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// * 232 ticks will occur 32 clock cycles after the previous tick
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// By default every delta is equal to 33.
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// Every five ticks (20%, 200 delta in one second), the delta is equal to 32
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// The remaining (32) deltas equal to 32 are distributed using primes numbers.
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static uint32_t counter = 0;
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if ((counter % 5) == 0 || (counter % 31) == 0 || (counter % 139) == 0 || (counter == 503)) {
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delta = 32;
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} else {
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delta = 33;
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}
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++counter;
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if (counter == 1000) {
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counter = 0;
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}
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}
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return delta;
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}
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static inline void clear_tick_interrupt() {
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nrf_rtc_event_clear(COMMON_RTC_INSTANCE, OS_TICK_EVENT);
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nrf_rtc_event_disable(COMMON_RTC_INSTANCE, OS_TICK_INT_MASK);
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}
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/**
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* Indicate if a value is included in a range which can be wrapped.
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* @param begin start of the range
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* @param end end of the range
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* @param val value to check
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* @return true if the value is included in the range and false otherwise.
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*/
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static inline bool is_in_wrapped_range(uint32_t begin, uint32_t end, uint32_t val) {
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// regular case, begin < end
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// return true if begin <= val < end
|
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if (begin < end) {
|
||||
if (begin <= val && val < end) {
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return true;
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} else {
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return false;
|
||||
}
|
||||
} else {
|
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// In this case end < begin because it has wrap around the limits
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// return false if end < val < begin
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if (end < val && val < begin) {
|
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return false;
|
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} else {
|
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return true;
|
||||
}
|
||||
}
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|
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}
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||||
|
||||
/**
|
||||
* Register the next tick.
|
||||
*/
|
||||
static void register_next_tick() {
|
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previous_tick_cc_value = nrf_rtc_cc_get(COMMON_RTC_INSTANCE, OS_TICK_CC_CHANNEL);
|
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uint32_t delta = get_next_tick_cc_delta();
|
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uint32_t new_compare_value = (previous_tick_cc_value + delta) & MAX_RTC_COUNTER_VAL;
|
||||
|
||||
// Disable irq directly for few cycles,
|
||||
// Validation of the new CC value against the COUNTER,
|
||||
// Setting the new CC value and enabling CC IRQ should be an atomic operation
|
||||
// Otherwise, there is a possibility to set an invalid CC value because
|
||||
// the RTC1 keeps running.
|
||||
// This code is very short 20-38 cycles in the worst case, it shouldn't
|
||||
// disturb softdevice.
|
||||
__disable_irq();
|
||||
uint32_t current_counter = nrf_rtc_counter_get(COMMON_RTC_INSTANCE);
|
||||
|
||||
// If an overflow occur, set the next tick in COUNTER + delta clock cycles
|
||||
if (is_in_wrapped_range(previous_tick_cc_value, new_compare_value, current_counter) == false) {
|
||||
new_compare_value = current_counter + delta;
|
||||
}
|
||||
nrf_rtc_cc_set(COMMON_RTC_INSTANCE, OS_TICK_CC_CHANNEL, new_compare_value);
|
||||
// Enable generation of the compare event for the value set above (this
|
||||
// event will trigger the interrupt).
|
||||
nrf_rtc_event_enable(COMMON_RTC_INSTANCE, OS_TICK_INT_MASK);
|
||||
__enable_irq();
|
||||
}
|
||||
|
||||
/**
|
||||
* Initialize alternative hardware timer as RTX kernel timer
|
||||
* This function is directly called by RTX.
|
||||
* @note this function shouldn't be called directly.
|
||||
* @return IRQ number of the alternative hardware timer
|
||||
*/
|
||||
int os_tick_init (void)
|
||||
{
|
||||
common_rtc_init();
|
||||
|
||||
nrf_rtc_cc_set(COMMON_RTC_INSTANCE, OS_TICK_CC_CHANNEL, 0);
|
||||
register_next_tick();
|
||||
|
||||
return nrf_drv_get_IRQn(COMMON_RTC_INSTANCE);
|
||||
}
|
||||
|
||||
/**
|
||||
* Acknowledge the tick interrupt.
|
||||
* This function is called by the function OS_Tick_Handler of RTX.
|
||||
* @note this function shouldn't be called directly.
|
||||
*/
|
||||
void os_tick_irqack(void)
|
||||
{
|
||||
clear_tick_interrupt();
|
||||
register_next_tick();
|
||||
}
|
||||
|
||||
/**
|
||||
* Returns the overflow flag of the alternative hardware timer.
|
||||
* @note This function is exposed by RTX kernel.
|
||||
* @return 1 if the timer has overflowed and 0 otherwise.
|
||||
*/
|
||||
uint32_t os_tick_ovf(void) {
|
||||
uint32_t current_counter = nrf_rtc_counter_get(COMMON_RTC_INSTANCE);
|
||||
uint32_t next_tick_cc_value = nrf_rtc_cc_get(COMMON_RTC_INSTANCE, OS_TICK_CC_CHANNEL);
|
||||
|
||||
return is_in_wrapped_range(previous_tick_cc_value, next_tick_cc_value, current_counter) ? 0 : 1;
|
||||
}
|
||||
|
||||
/**
|
||||
* Return the value of the alternative hardware timer.
|
||||
* @note The documentation is not very clear about what is expected as a result,
|
||||
* is it an ascending counter, a descending one ?
|
||||
* None of this is specified.
|
||||
* The default systick is a descending counter and this function return values in
|
||||
* descending order, even if the internal counter used is an ascending one.
|
||||
* @return the value of the alternative hardware timer.
|
||||
*/
|
||||
uint32_t os_tick_val(void) {
|
||||
uint32_t current_counter = nrf_rtc_counter_get(COMMON_RTC_INSTANCE);
|
||||
uint32_t next_tick_cc_value = nrf_rtc_cc_get(COMMON_RTC_INSTANCE, OS_TICK_CC_CHANNEL);
|
||||
|
||||
// do not use os_tick_ovf because its counter value can be different
|
||||
if(is_in_wrapped_range(previous_tick_cc_value, next_tick_cc_value, current_counter)) {
|
||||
if (next_tick_cc_value > previous_tick_cc_value) {
|
||||
return next_tick_cc_value - current_counter;
|
||||
} else if(current_counter <= next_tick_cc_value) {
|
||||
return next_tick_cc_value - current_counter;
|
||||
} else {
|
||||
return next_tick_cc_value + (MAX_RTC_COUNTER_VAL - current_counter);
|
||||
}
|
||||
} else {
|
||||
// use (os_trv + 1) has the base step, can be totally inacurate ...
|
||||
uint32_t clock_cycles_by_tick = os_trv + 1;
|
||||
|
||||
// if current counter has wrap arround, add the limit to it.
|
||||
if (current_counter < next_tick_cc_value) {
|
||||
current_counter = current_counter + MAX_RTC_COUNTER_VAL;
|
||||
}
|
||||
|
||||
return clock_cycles_by_tick - ((current_counter - next_tick_cc_value) % clock_cycles_by_tick);
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
#endif // defined(TARGET_MCU_NRF51822)
|
||||
|
|
@ -39,13 +39,13 @@
|
|||
#include "us_ticker_api.h"
|
||||
#include "common_rtc.h"
|
||||
#include "app_util.h"
|
||||
#include "nrf_drv_common.h"
|
||||
#include "lp_ticker_api.h"
|
||||
|
||||
|
||||
//------------------------------------------------------------------------------
|
||||
// Common stuff used also by lp_ticker and rtc_api (see "common_rtc.h").
|
||||
//
|
||||
#include "nrf_drv_clock.h"
|
||||
#include "app_util_platform.h"
|
||||
|
||||
bool m_common_rtc_enabled = false;
|
||||
|
|
@ -217,3 +217,346 @@ void us_ticker_clear_interrupt(void)
|
|||
{
|
||||
nrf_rtc_event_clear(COMMON_RTC_INSTANCE, US_TICKER_EVENT);
|
||||
}
|
||||
|
||||
|
||||
// Since there is no SysTick on NRF51, the RTC1 channel 1 is used as an
|
||||
// alternative source of RTOS ticks.
|
||||
#if defined(TARGET_MCU_NRF51822)
|
||||
|
||||
#include "toolchain.h"
|
||||
|
||||
|
||||
#define MAX_RTC_COUNTER_VAL ((1uL << RTC_COUNTER_BITS) - 1)
|
||||
|
||||
/**
|
||||
* The value previously set in the capture compare register of channel 1
|
||||
*/
|
||||
static uint32_t previous_tick_cc_value = 0;
|
||||
|
||||
/*
|
||||
RTX provide the following definitions which are used by the tick code:
|
||||
* os_trv: The number (minus 1) of clock cycle between two tick.
|
||||
* os_clockrate: Time duration between two ticks (in us).
|
||||
* OS_Tick_Handler: The function which handle a tick event.
|
||||
This function is special because it never returns.
|
||||
Those definitions are used by the code which handle the os tick.
|
||||
To allow compilation of us_ticker programs without RTOS, those symbols are
|
||||
exported from this module as weak ones.
|
||||
*/
|
||||
MBED_WEAK uint32_t const os_trv;
|
||||
MBED_WEAK uint32_t const os_clockrate;
|
||||
MBED_WEAK void OS_Tick_Handler() { }
|
||||
|
||||
|
||||
#if defined (__CC_ARM) /* ARMCC Compiler */
|
||||
|
||||
__asm void COMMON_RTC_IRQ_HANDLER(void)
|
||||
{
|
||||
IMPORT OS_Tick_Handler
|
||||
IMPORT common_rtc_irq_handler
|
||||
|
||||
/**
|
||||
* Chanel 1 of RTC1 is used by RTX as a systick.
|
||||
* If the compare event on channel 1 is set, then branch to OS_Tick_Handler.
|
||||
* Otherwise, just execute common_rtc_irq_handler.
|
||||
* This function has to be written in assembly and tagged as naked because OS_Tick_Handler
|
||||
* will never return.
|
||||
* A c function would put lr on the stack before calling OS_Tick_Handler and this value
|
||||
* would never been dequeued.
|
||||
*
|
||||
* \code
|
||||
* void COMMON_RTC_IRQ_HANDLER(void) {
|
||||
if(NRF_RTC1->EVENTS_COMPARE[1]) {
|
||||
// never return...
|
||||
OS_Tick_Handler();
|
||||
} else {
|
||||
common_rtc_irq_handler();
|
||||
}
|
||||
}
|
||||
* \endcode
|
||||
*/
|
||||
ldr r0,=0x40011144
|
||||
ldr r1, [r0, #0]
|
||||
cmp r1, #0
|
||||
beq US_TICKER_HANDLER
|
||||
bl OS_Tick_Handler
|
||||
US_TICKER_HANDLER
|
||||
push {r3, lr}
|
||||
bl common_rtc_irq_handler
|
||||
pop {r3, pc}
|
||||
nop /* padding */
|
||||
}
|
||||
|
||||
#elif defined (__GNUC__) /* GNU Compiler */
|
||||
|
||||
__attribute__((naked)) void COMMON_RTC_IRQ_HANDLER(void)
|
||||
{
|
||||
/**
|
||||
* Chanel 1 of RTC1 is used by RTX as a systick.
|
||||
* If the compare event on channel 1 is set, then branch to OS_Tick_Handler.
|
||||
* Otherwise, just execute common_rtc_irq_handler.
|
||||
* This function has to be written in assembly and tagged as naked because OS_Tick_Handler
|
||||
* will never return.
|
||||
* A c function would put lr on the stack before calling OS_Tick_Handler and this value
|
||||
* would never been dequeued.
|
||||
*
|
||||
* \code
|
||||
* void COMMON_RTC_IRQ_HANDLER(void) {
|
||||
if(NRF_RTC1->EVENTS_COMPARE[1]) {
|
||||
// never return...
|
||||
OS_Tick_Handler();
|
||||
} else {
|
||||
common_rtc_irq_handler();
|
||||
}
|
||||
}
|
||||
* \endcode
|
||||
*/
|
||||
__asm__ (
|
||||
"ldr r0,=0x40011144\n"
|
||||
"ldr r1, [r0, #0]\n"
|
||||
"cmp r1, #0\n"
|
||||
"beq US_TICKER_HANDLER\n"
|
||||
"bl OS_Tick_Handler\n"
|
||||
"US_TICKER_HANDLER:\n"
|
||||
"push {r3, lr}\n"
|
||||
"bl common_rtc_irq_handler\n"
|
||||
"pop {r3, pc}\n"
|
||||
"nop"
|
||||
);
|
||||
}
|
||||
|
||||
#elif defined (__ICCARM__)//IAR
|
||||
void common_rtc_irq_handler(void);
|
||||
|
||||
__stackless __task void COMMON_RTC_IRQ_HANDLER(void)
|
||||
{
|
||||
uint32_t temp;
|
||||
|
||||
__asm volatile(
|
||||
" ldr %[temp], [%[reg2check]] \n"
|
||||
" cmp %[temp], #0 \n"
|
||||
" beq 1f \n"
|
||||
" bl.w OS_Tick_Handler \n"
|
||||
"1: \n"
|
||||
" push {r3, lr}\n"
|
||||
" blx %[rtc_irq] \n"
|
||||
" pop {r3, pc}\n"
|
||||
|
||||
: /* Outputs */
|
||||
[temp] "=&r"(temp)
|
||||
: /* Inputs */
|
||||
[reg2check] "r"(0x40011144),
|
||||
[rtc_irq] "r"(common_rtc_irq_handler)
|
||||
: /* Clobbers */
|
||||
"cc"
|
||||
);
|
||||
(void)temp;
|
||||
}
|
||||
|
||||
|
||||
#else
|
||||
|
||||
#error Compiler not supported.
|
||||
#error Provide a definition of COMMON_RTC_IRQ_HANDLER.
|
||||
|
||||
/*
|
||||
* Chanel 1 of RTC1 is used by RTX as a systick.
|
||||
* If the compare event on channel 1 is set, then branch to OS_Tick_Handler.
|
||||
* Otherwise, just execute common_rtc_irq_handler.
|
||||
* This function has to be written in assembly and tagged as naked because OS_Tick_Handler
|
||||
* will never return.
|
||||
* A c function would put lr on the stack before calling OS_Tick_Handler and this value
|
||||
* will never been dequeued. After a certain time a stack overflow will happen.
|
||||
*
|
||||
* \code
|
||||
* void COMMON_RTC_IRQ_HANDLER(void) {
|
||||
if(NRF_RTC1->EVENTS_COMPARE[1]) {
|
||||
// never return...
|
||||
OS_Tick_Handler();
|
||||
} else {
|
||||
common_rtc_irq_handler();
|
||||
}
|
||||
}
|
||||
* \endcode
|
||||
*/
|
||||
|
||||
#endif
|
||||
|
||||
/**
|
||||
* Return the next number of clock cycle needed for the next tick.
|
||||
* @note This function has been carrefuly optimized for a systick occuring every 1000us.
|
||||
*/
|
||||
static uint32_t get_next_tick_cc_delta() {
|
||||
uint32_t delta = 0;
|
||||
|
||||
if (os_clockrate != 1000) {
|
||||
// In RTX, by default SYSTICK is is used.
|
||||
// A tick event is generated every os_trv + 1 clock cycles of the system timer.
|
||||
delta = os_trv + 1;
|
||||
} else {
|
||||
// If the clockrate is set to 1000us then 1000 tick should happen every second.
|
||||
// Unfortunatelly, when clockrate is set to 1000, os_trv is equal to 31.
|
||||
// If (os_trv + 1) is used as the delta value between two ticks, 1000 ticks will be
|
||||
// generated in 32000 clock cycle instead of 32768 clock cycles.
|
||||
// As a result, if a user schedule an OS timer to start in 100s, the timer will start
|
||||
// instead after 97.656s
|
||||
// The code below fix this issue, a clock rate of 1000s will generate 1000 ticks in 32768
|
||||
// clock cycles.
|
||||
// The strategy is simple, for 1000 ticks:
|
||||
// * 768 ticks will occur 33 clock cycles after the previous tick
|
||||
// * 232 ticks will occur 32 clock cycles after the previous tick
|
||||
// By default every delta is equal to 33.
|
||||
// Every five ticks (20%, 200 delta in one second), the delta is equal to 32
|
||||
// The remaining (32) deltas equal to 32 are distributed using primes numbers.
|
||||
static uint32_t counter = 0;
|
||||
if ((counter % 5) == 0 || (counter % 31) == 0 || (counter % 139) == 0 || (counter == 503)) {
|
||||
delta = 32;
|
||||
} else {
|
||||
delta = 33;
|
||||
}
|
||||
++counter;
|
||||
if (counter == 1000) {
|
||||
counter = 0;
|
||||
}
|
||||
}
|
||||
return delta;
|
||||
}
|
||||
|
||||
static inline void clear_tick_interrupt() {
|
||||
nrf_rtc_event_clear(COMMON_RTC_INSTANCE, OS_TICK_EVENT);
|
||||
nrf_rtc_event_disable(COMMON_RTC_INSTANCE, OS_TICK_INT_MASK);
|
||||
}
|
||||
|
||||
/**
|
||||
* Indicate if a value is included in a range which can be wrapped.
|
||||
* @param begin start of the range
|
||||
* @param end end of the range
|
||||
* @param val value to check
|
||||
* @return true if the value is included in the range and false otherwise.
|
||||
*/
|
||||
static inline bool is_in_wrapped_range(uint32_t begin, uint32_t end, uint32_t val) {
|
||||
// regular case, begin < end
|
||||
// return true if begin <= val < end
|
||||
if (begin < end) {
|
||||
if (begin <= val && val < end) {
|
||||
return true;
|
||||
} else {
|
||||
return false;
|
||||
}
|
||||
} else {
|
||||
// In this case end < begin because it has wrap around the limits
|
||||
// return false if end < val < begin
|
||||
if (end < val && val < begin) {
|
||||
return false;
|
||||
} else {
|
||||
return true;
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
/**
|
||||
* Register the next tick.
|
||||
*/
|
||||
static void register_next_tick() {
|
||||
previous_tick_cc_value = nrf_rtc_cc_get(COMMON_RTC_INSTANCE, OS_TICK_CC_CHANNEL);
|
||||
uint32_t delta = get_next_tick_cc_delta();
|
||||
uint32_t new_compare_value = (previous_tick_cc_value + delta) & MAX_RTC_COUNTER_VAL;
|
||||
|
||||
// Disable irq directly for few cycles,
|
||||
// Validation of the new CC value against the COUNTER,
|
||||
// Setting the new CC value and enabling CC IRQ should be an atomic operation
|
||||
// Otherwise, there is a possibility to set an invalid CC value because
|
||||
// the RTC1 keeps running.
|
||||
// This code is very short 20-38 cycles in the worst case, it shouldn't
|
||||
// disturb softdevice.
|
||||
__disable_irq();
|
||||
uint32_t current_counter = nrf_rtc_counter_get(COMMON_RTC_INSTANCE);
|
||||
|
||||
// If an overflow occur, set the next tick in COUNTER + delta clock cycles
|
||||
if (is_in_wrapped_range(previous_tick_cc_value, new_compare_value, current_counter) == false) {
|
||||
new_compare_value = current_counter + delta;
|
||||
}
|
||||
nrf_rtc_cc_set(COMMON_RTC_INSTANCE, OS_TICK_CC_CHANNEL, new_compare_value);
|
||||
// Enable generation of the compare event for the value set above (this
|
||||
// event will trigger the interrupt).
|
||||
nrf_rtc_event_enable(COMMON_RTC_INSTANCE, OS_TICK_INT_MASK);
|
||||
__enable_irq();
|
||||
}
|
||||
|
||||
/**
|
||||
* Initialize alternative hardware timer as RTX kernel timer
|
||||
* This function is directly called by RTX.
|
||||
* @note this function shouldn't be called directly.
|
||||
* @return IRQ number of the alternative hardware timer
|
||||
*/
|
||||
int os_tick_init (void)
|
||||
{
|
||||
common_rtc_init();
|
||||
|
||||
nrf_rtc_cc_set(COMMON_RTC_INSTANCE, OS_TICK_CC_CHANNEL, 0);
|
||||
register_next_tick();
|
||||
|
||||
return nrf_drv_get_IRQn(COMMON_RTC_INSTANCE);
|
||||
}
|
||||
|
||||
/**
|
||||
* Acknowledge the tick interrupt.
|
||||
* This function is called by the function OS_Tick_Handler of RTX.
|
||||
* @note this function shouldn't be called directly.
|
||||
*/
|
||||
void os_tick_irqack(void)
|
||||
{
|
||||
clear_tick_interrupt();
|
||||
register_next_tick();
|
||||
}
|
||||
|
||||
/**
|
||||
* Returns the overflow flag of the alternative hardware timer.
|
||||
* @note This function is exposed by RTX kernel.
|
||||
* @return 1 if the timer has overflowed and 0 otherwise.
|
||||
*/
|
||||
uint32_t os_tick_ovf(void) {
|
||||
uint32_t current_counter = nrf_rtc_counter_get(COMMON_RTC_INSTANCE);
|
||||
uint32_t next_tick_cc_value = nrf_rtc_cc_get(COMMON_RTC_INSTANCE, OS_TICK_CC_CHANNEL);
|
||||
|
||||
return is_in_wrapped_range(previous_tick_cc_value, next_tick_cc_value, current_counter) ? 0 : 1;
|
||||
}
|
||||
|
||||
/**
|
||||
* Return the value of the alternative hardware timer.
|
||||
* @note The documentation is not very clear about what is expected as a result,
|
||||
* is it an ascending counter, a descending one ?
|
||||
* None of this is specified.
|
||||
* The default systick is a descending counter and this function return values in
|
||||
* descending order, even if the internal counter used is an ascending one.
|
||||
* @return the value of the alternative hardware timer.
|
||||
*/
|
||||
uint32_t os_tick_val(void) {
|
||||
uint32_t current_counter = nrf_rtc_counter_get(COMMON_RTC_INSTANCE);
|
||||
uint32_t next_tick_cc_value = nrf_rtc_cc_get(COMMON_RTC_INSTANCE, OS_TICK_CC_CHANNEL);
|
||||
|
||||
// do not use os_tick_ovf because its counter value can be different
|
||||
if(is_in_wrapped_range(previous_tick_cc_value, next_tick_cc_value, current_counter)) {
|
||||
if (next_tick_cc_value > previous_tick_cc_value) {
|
||||
return next_tick_cc_value - current_counter;
|
||||
} else if(current_counter <= next_tick_cc_value) {
|
||||
return next_tick_cc_value - current_counter;
|
||||
} else {
|
||||
return next_tick_cc_value + (MAX_RTC_COUNTER_VAL - current_counter);
|
||||
}
|
||||
} else {
|
||||
// use (os_trv + 1) has the base step, can be totally inacurate ...
|
||||
uint32_t clock_cycles_by_tick = os_trv + 1;
|
||||
|
||||
// if current counter has wrap arround, add the limit to it.
|
||||
if (current_counter < next_tick_cc_value) {
|
||||
current_counter = current_counter + MAX_RTC_COUNTER_VAL;
|
||||
}
|
||||
|
||||
return clock_cycles_by_tick - ((current_counter - next_tick_cc_value) % clock_cycles_by_tick);
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
#endif // defined(TARGET_MCU_NRF51822)
|
||||
|
|
|
|||
Loading…
Reference in New Issue