454 lines
14 KiB
C
454 lines
14 KiB
C
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
// am_hal_systick.c
|
||
|
|
//! @file
|
||
|
|
//!
|
||
|
|
//! @brief Functions for interfacing with the SYSTICK
|
||
|
|
//!
|
||
|
|
//! @addtogroup systick2 System Timer (SYSTICK)
|
||
|
|
//! @ingroup apollo2hal
|
||
|
|
//! @{
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
// Copyright (c) 2017, Ambiq Micro
|
||
|
|
// All rights reserved.
|
||
|
|
//
|
||
|
|
// 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 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 the copyright holder nor the names of its
|
||
|
|
// contributors may be used to endorse or promote products derived from this
|
||
|
|
// software without specific prior written permission.
|
||
|
|
//
|
||
|
|
// 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 ANY THEORY OF LIABILITY, WHETHER IN
|
||
|
|
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
||
|
|
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
||
|
|
// POSSIBILITY OF SUCH DAMAGE.
|
||
|
|
//
|
||
|
|
// This is part of revision 1.2.9 of the AmbiqSuite Development Package.
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
|
||
|
|
#include <stdint.h>
|
||
|
|
#include <stdbool.h>
|
||
|
|
#include "am_mcu_apollo.h"
|
||
|
|
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
// Macro definitions
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
#define SYSTICK_MAX_TICKS ((1 << 24)-1)
|
||
|
|
#define MAX_U32 (0xffffffff)
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
//! @brief Start the SYSTICK.
|
||
|
|
//!
|
||
|
|
//! This function starts the systick timer.
|
||
|
|
//!
|
||
|
|
//! @note This timer does not run in deep-sleep mode as it runs from the core
|
||
|
|
//! clock, which is gated in deep-sleep. If a timer is needed in deep-sleep use
|
||
|
|
//! one of the ctimers instead. Also to note is this timer will consume higher
|
||
|
|
//! power than the ctimers.
|
||
|
|
//!
|
||
|
|
//! @return None.
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
void
|
||
|
|
am_hal_systick_start(void)
|
||
|
|
{
|
||
|
|
//
|
||
|
|
// Start the systick timer.
|
||
|
|
//
|
||
|
|
AM_REG(SYSTICK, SYSTCSR) |= AM_REG_SYSTICK_SYSTCSR_ENABLE_M;
|
||
|
|
}
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
//! @brief Stop the SYSTICK.
|
||
|
|
//!
|
||
|
|
//! This function stops the systick timer.
|
||
|
|
//!
|
||
|
|
//! @note This timer does not run in deep-sleep mode as it runs from the core
|
||
|
|
//! clock, which is gated in deep-sleep. If a timer is needed in deep-sleep use
|
||
|
|
//! one of the ctimers instead. Also to note is this timer will consume higher
|
||
|
|
//! power than the ctimers.
|
||
|
|
//!
|
||
|
|
//! @return None.
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
void
|
||
|
|
am_hal_systick_stop(void)
|
||
|
|
{
|
||
|
|
//
|
||
|
|
// Stop the systick timer.
|
||
|
|
//
|
||
|
|
AM_REG(SYSTICK, SYSTCSR) &= ~AM_REG_SYSTICK_SYSTCSR_ENABLE_M;
|
||
|
|
}
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
//! @brief Enable the interrupt in the SYSTICK.
|
||
|
|
//!
|
||
|
|
//! This function enables the interupt in the systick timer.
|
||
|
|
//!
|
||
|
|
//! @return None.
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
void
|
||
|
|
am_hal_systick_int_enable(void)
|
||
|
|
{
|
||
|
|
//
|
||
|
|
// Enable the systick timer interrupt.
|
||
|
|
//
|
||
|
|
AM_REG(SYSTICK, SYSTCSR) |= AM_REG_SYSTICK_SYSTCSR_TICKINT_M;
|
||
|
|
}
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
//! @brief Disable the interrupt in the SYSTICK.
|
||
|
|
//!
|
||
|
|
//! This function disables the interupt in the systick timer.
|
||
|
|
//!
|
||
|
|
//! @return None.
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
void
|
||
|
|
am_hal_systick_int_disable(void)
|
||
|
|
{
|
||
|
|
//
|
||
|
|
// Disable the systick timer interrupt.
|
||
|
|
//
|
||
|
|
AM_REG(SYSTICK, SYSTCSR) &= ~AM_REG_SYSTICK_SYSTCSR_TICKINT_M;
|
||
|
|
}
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
//! @brief Reads the interrupt status.
|
||
|
|
//!
|
||
|
|
//! This function reads the interrupt status in the systick timer.
|
||
|
|
//!
|
||
|
|
//! @return the interrupt status.
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
uint32_t
|
||
|
|
am_hal_systick_int_status_get(void)
|
||
|
|
{
|
||
|
|
//
|
||
|
|
// Return the systick timer interrupt status.
|
||
|
|
//
|
||
|
|
return AM_REG(SYSTICK, SYSTCSR) & AM_REG_SYSTICK_SYSTCSR_COUNTFLAG_M;
|
||
|
|
}
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
//! @brief Reset the interrupt in the SYSTICK.
|
||
|
|
//!
|
||
|
|
//! This function resets the systick timer by clearing out the configuration
|
||
|
|
//! register.
|
||
|
|
//!
|
||
|
|
//! @return None.
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
void
|
||
|
|
am_hal_systick_reset(void)
|
||
|
|
{
|
||
|
|
//
|
||
|
|
// Reset the systick timer interrupt.
|
||
|
|
//
|
||
|
|
AM_REG(SYSTICK, SYSTCSR) = 0x0;
|
||
|
|
}
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
//! @brief Load the value into the SYSTICK.
|
||
|
|
//!
|
||
|
|
//! @param ui32LoadVal the desired load value for the systick. Maximum value is
|
||
|
|
//! 0x00FF.FFFF.
|
||
|
|
//!
|
||
|
|
//! This function loads the desired value into the systick timer.
|
||
|
|
//!
|
||
|
|
//! @return None.
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
void
|
||
|
|
am_hal_systick_load(uint32_t ui32LoadVal)
|
||
|
|
{
|
||
|
|
//
|
||
|
|
// Write the reload register.
|
||
|
|
//
|
||
|
|
AM_REG(SYSTICK, SYSTRVR) = ui32LoadVal;
|
||
|
|
}
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
//! @brief Get the current count value in the SYSTICK.
|
||
|
|
//!
|
||
|
|
//! This function gets the current count value in the systick timer.
|
||
|
|
//!
|
||
|
|
//! @return Current count value.
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
uint32_t
|
||
|
|
am_hal_systick_count(void)
|
||
|
|
{
|
||
|
|
//
|
||
|
|
// Return the current systick timer count value.
|
||
|
|
//
|
||
|
|
return AM_REG(SYSTICK, SYSTCVR);
|
||
|
|
}
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
//! @brief Wait the specified number of ticks.
|
||
|
|
//!
|
||
|
|
//! This function delays for the given number of SysTick ticks.
|
||
|
|
//!
|
||
|
|
//! @note If the SysTick timer is being used elsewhere, it will be corrupted
|
||
|
|
//! by calling this function.
|
||
|
|
//!
|
||
|
|
//! @return 0 if successful.
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
uint32_t
|
||
|
|
am_hal_systick_wait_ticks(uint32_t u32Ticks)
|
||
|
|
{
|
||
|
|
|
||
|
|
if ( u32Ticks == 0 )
|
||
|
|
{
|
||
|
|
u32Ticks++; // Make sure we get the COUNTFLAG
|
||
|
|
}
|
||
|
|
|
||
|
|
//
|
||
|
|
// The proper SysTick initialization sequence is: (p 4-36 of the M4 UG).
|
||
|
|
// 1. Program reload value
|
||
|
|
// 2. Clear current value
|
||
|
|
// 3. Program CSR
|
||
|
|
//
|
||
|
|
// Set the reload value to the required number of ticks.
|
||
|
|
//
|
||
|
|
AM_REG(SYSTICK, SYSTRVR) = u32Ticks;
|
||
|
|
|
||
|
|
//
|
||
|
|
// Clear the current count.
|
||
|
|
//
|
||
|
|
AM_REG(SYSTICK, SYSTCVR) = 0x0;
|
||
|
|
|
||
|
|
//
|
||
|
|
// Set to use the processor clock, but don't cause an exception (we'll poll).
|
||
|
|
//
|
||
|
|
AM_REG(SYSTICK, SYSTCSR) = AM_REG_SYSTICK_SYSTCSR_ENABLE_M;
|
||
|
|
|
||
|
|
//
|
||
|
|
// Poll till done
|
||
|
|
//
|
||
|
|
while ( !(AM_REG(SYSTICK, SYSTCSR) & AM_REG_SYSTICK_SYSTCSR_COUNTFLAG_M) );
|
||
|
|
|
||
|
|
//
|
||
|
|
// And disable systick before exiting.
|
||
|
|
//
|
||
|
|
AM_REG(SYSTICK, SYSTCSR) = 0;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
//! @brief Delay the specified number of microseconds.
|
||
|
|
//!
|
||
|
|
//! This function will use the SysTick timer to delay until the specified
|
||
|
|
//! number of microseconds have elapsed. It uses the processor clocks and
|
||
|
|
//! takes into account the current CORESEL setting.
|
||
|
|
//!
|
||
|
|
//! @note If the SysTick timer is being used elsewhere, it will be corrupted
|
||
|
|
//! by calling this function.
|
||
|
|
//!
|
||
|
|
//! @return Total number of SysTick ticks delayed.
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|
||
|
|
uint32_t
|
||
|
|
am_hal_systick_delay_us(uint32_t u32NumUs)
|
||
|
|
{
|
||
|
|
uint32_t u32ClkFreq, u32nLoops, u32Ticks, uRet;
|
||
|
|
uint32_t u32CoreSel = AM_BFR(CLKGEN, CCTRL, CORESEL);
|
||
|
|
|
||
|
|
u32nLoops = 1;
|
||
|
|
switch (u32CoreSel)
|
||
|
|
{
|
||
|
|
//
|
||
|
|
// We need to compute the required number of ticks. To do so and to
|
||
|
|
// minimize divide operations, we'll use the following equation:
|
||
|
|
// u32Ticks = (u32NumUs * HFCR_EXACT)/1000000
|
||
|
|
// = (u32NumUs * (HFCR_EXACT * 1024)/1000000) / 1024
|
||
|
|
// The values for the variable u32ClkFreq are computed as follows:
|
||
|
|
// u32ClkFreq = (24390200 * 1024) / ((clksel+1)*1000000);
|
||
|
|
// (and we'll do the remaining divide by 1024, using a shift, later).
|
||
|
|
//
|
||
|
|
case 0:
|
||
|
|
u32ClkFreq = 24975;
|
||
|
|
if ( u32NumUs > ((SYSTICK_MAX_TICKS / 24975)*1024) )
|
||
|
|
{
|
||
|
|
u32nLoops = (u32NumUs / ((SYSTICK_MAX_TICKS / 24975)*1024)) + 1;
|
||
|
|
u32NumUs /= u32nLoops;
|
||
|
|
}
|
||
|
|
if ( u32NumUs > (MAX_U32 / 24975) )
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs >> 10) * u32ClkFreq;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs * u32ClkFreq) >> 10;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case 1:
|
||
|
|
u32ClkFreq = 12487;
|
||
|
|
if ( u32NumUs > ((SYSTICK_MAX_TICKS / 12487)*1024) )
|
||
|
|
{
|
||
|
|
u32nLoops = (u32NumUs / ((SYSTICK_MAX_TICKS / 12487)*1024)) + 1;
|
||
|
|
u32NumUs /= u32nLoops;
|
||
|
|
}
|
||
|
|
if ( u32NumUs > (MAX_U32 / 12487) )
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs >> 10) * u32ClkFreq;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs * u32ClkFreq) >> 10;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case 2:
|
||
|
|
u32ClkFreq = 8325;
|
||
|
|
if ( u32NumUs > ((SYSTICK_MAX_TICKS / 8325)*1024) )
|
||
|
|
{
|
||
|
|
u32nLoops = (u32NumUs / ((SYSTICK_MAX_TICKS / 8325)*1024)) + 1;
|
||
|
|
u32NumUs /= u32nLoops;
|
||
|
|
}
|
||
|
|
if ( u32NumUs > (MAX_U32 / 8325) )
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs >> 10) * u32ClkFreq;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs * u32ClkFreq) >> 10;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case 3:
|
||
|
|
u32ClkFreq = 6243;
|
||
|
|
if ( u32NumUs > ((SYSTICK_MAX_TICKS / 6243)*1024) )
|
||
|
|
{
|
||
|
|
u32nLoops = (u32NumUs / ((SYSTICK_MAX_TICKS / 6243)*1024)) + 1;
|
||
|
|
u32NumUs /= u32nLoops;
|
||
|
|
}
|
||
|
|
if ( u32NumUs > (MAX_U32 / 6243) )
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs >> 10) * u32ClkFreq;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs * u32ClkFreq) >> 10;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case 4:
|
||
|
|
u32ClkFreq = 4995;
|
||
|
|
if ( u32NumUs > ((SYSTICK_MAX_TICKS / 4995)*1024) )
|
||
|
|
{
|
||
|
|
u32nLoops = (u32NumUs / ((SYSTICK_MAX_TICKS / 4995)*1024)) + 1;
|
||
|
|
u32NumUs /= u32nLoops;
|
||
|
|
}
|
||
|
|
if ( u32NumUs > (MAX_U32 / 4995) )
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs >> 10) * u32ClkFreq;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs * u32ClkFreq) >> 10;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case 5:
|
||
|
|
u32ClkFreq = 4162;
|
||
|
|
if ( u32NumUs > ((SYSTICK_MAX_TICKS / 4162)*1024) )
|
||
|
|
{
|
||
|
|
u32nLoops = (u32NumUs / ((SYSTICK_MAX_TICKS / 4162)*1024)) + 1;
|
||
|
|
u32NumUs /= u32nLoops;
|
||
|
|
}
|
||
|
|
if ( u32NumUs > (MAX_U32 / 4162) )
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs >> 10) * u32ClkFreq;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs * u32ClkFreq) >> 10;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case 6:
|
||
|
|
u32ClkFreq = 3567;
|
||
|
|
if ( u32NumUs > ((SYSTICK_MAX_TICKS / 3567)*1024) )
|
||
|
|
{
|
||
|
|
u32nLoops = (u32NumUs / ((SYSTICK_MAX_TICKS / 3567)*1024)) + 1;
|
||
|
|
u32NumUs /= u32nLoops;
|
||
|
|
}
|
||
|
|
if ( u32NumUs > (MAX_U32 / 3567) )
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs >> 10) * u32ClkFreq;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs * u32ClkFreq) >> 10;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case 7:
|
||
|
|
u32ClkFreq = 3121;
|
||
|
|
if ( u32NumUs > ((SYSTICK_MAX_TICKS / 3121)*1024) )
|
||
|
|
{
|
||
|
|
u32nLoops = (u32NumUs / ((SYSTICK_MAX_TICKS / 3121)*1024)) + 1;
|
||
|
|
u32NumUs /= u32nLoops;
|
||
|
|
}
|
||
|
|
if ( u32NumUs > (MAX_U32 / 3121) )
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs >> 10) * u32ClkFreq;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
u32Ticks = (u32NumUs * u32ClkFreq) >> 10;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
default:
|
||
|
|
u32Ticks = 1;
|
||
|
|
break;
|
||
|
|
} // switch()
|
||
|
|
|
||
|
|
uRet = u32Ticks * u32nLoops;
|
||
|
|
while ( u32nLoops-- )
|
||
|
|
{
|
||
|
|
am_hal_systick_wait_ticks(u32Ticks);
|
||
|
|
}
|
||
|
|
|
||
|
|
return uRet;
|
||
|
|
}
|
||
|
|
|
||
|
|
//*****************************************************************************
|
||
|
|
//
|
||
|
|
// End Doxygen group.
|
||
|
|
//! @}
|
||
|
|
//
|
||
|
|
//*****************************************************************************
|