timer.c

ARM入门的好帮手.包含了从简单到相对较复杂的程序.

//*----------------------------------------------------------------------------
//*      ATMEL Microcontroller Software Support  -  ROUSSET  -
//*----------------------------------------------------------------------------
//* The software is delivered "AS IS" without warranty or condition of any
//* kind, either express, implied or statutory. This includes without
//* limitation any warranty or condition with respect to merchantability or
//* fitness for any particular purpose, or against the infringements of
//* intellectual property rights of others.
//*----------------------------------------------------------------------------
//* File Name           : timer.c
//* Object              : bench
//*
//* 1.0 15/05/01 JPP    : Creation
//*----------------------------------------------------------------------------


#include "periph/timer_counter/lib_tc.h"

#define     CHRONO_TC_INIT      ( TC_CLKS_MCK2              |\
                                  TC_WAVE | TC_CPCSTOP      |\
                                  TC_ASWTRG_CLEAR_OUTPUT )

#define     CHRONO_TC0_MODE    ( TC_CLKS_MCK2               |\
                                 TC_WAVE                    |\
                                 TC_CPCTRG                  |\
                                 TC_ACPA_CLEAR_OUTPUT       |\
                                 TC_ACPC_SET_OUTPUT         |\
                                 TC_ASWTRG_SET_OUTPUT )

#define     CHRONO_TC1_MODE    ( TC_CLKS_XC1                |\
                                 TC_WAVE                    |\
                                 TC_CPCTRG                  |\
                                 TC_ACPA_CLEAR_OUTPUT       |\
                                 TC_ACPC_SET_OUTPUT         |\
                                 TC_ASWTRG_SET_OUTPUT )

#define     CHRONO_TC2_MODE    ( TC_CLKS_XC2                |\
                                 TC_WAVE                    |\
                                 TC_CPCTRG                  |\
                                 TC_ACPA_CLEAR_OUTPUT       |\
                                 TC_ACPC_SET_OUTPUT         |\
                                 TC_ASWTRG_SET_OUTPUT )

//*----------------------------------------------------------------------------
//* Function Name       : at91_time_rtc_mcki
//* Object              : Calculate the MCKI
//* Input Parameters    : <TC_pt>  timer descriptor
//* Output Parameters   :
//*----------------------------------------------------------------------------
void at91_tc_open_count( const TCBlockDesc *TC_pt )
//* Begin
{

    u_int tmp;
    StructTCBlock   *tc_ptr = (StructTCBlock *)TC_pt->tc0_desc->tc_base ;

    //* Open timer for counting
    //* Open the Timer Counter channels
    at91_tc_open (TC_pt->tc0_desc, CHRONO_TC_INIT, TRUE, FALSE);
    at91_tc_open (TC_pt->tc1_desc, CHRONO_TC_INIT, TRUE, FALSE);
    at91_tc_open (TC_pt->tc2_desc, CHRONO_TC_INIT, TRUE, FALSE);

    //* Setup TIOA outputs to 0
    tc_ptr->TC[0].TC_RC = 2 ;
    tc_ptr->TC[0].TC_CCR = TC_CLKEN ;
    tc_ptr->TC[1].TC_RC = 2 ;
    tc_ptr->TC[1].TC_CCR = TC_CLKEN ;
    tc_ptr->TC[2].TC_RC = 2 ;
    tc_ptr->TC[2].TC_CCR = TC_CLKEN ;
    tc_ptr->TC_BCR = TC_SYNC ;

    //* Define the Timer Counter channel Chaining
    tc_ptr->TC_BMR = TC_TIOA0XC1 | TC_TIOA1XC2 ;

    //* Setup Timer 0
    tc_ptr->TC[0].TC_CMR = CHRONO_TC0_MODE ;
    tc_ptr->TC[0].TC_RC = 1000 ;
    tc_ptr->TC[0].TC_RA = 500 ;
    tc_ptr->TC[0].TC_CCR = TC_CLKEN ;

    //* Setup Timer 1
    tc_ptr->TC[1].TC_CMR = CHRONO_TC1_MODE ;
    tc_ptr->TC[1].TC_RC = 1000 ;
    tc_ptr->TC[1].TC_RA = 500 ;
    tc_ptr->TC[1].TC_CCR = TC_CLKEN ;

    //* Setup Timer 2
    tc_ptr->TC[2].TC_CMR = CHRONO_TC2_MODE ;
    tc_ptr->TC[2].TC_RC = 0xFFFF ;
    tc_ptr->TC[2].TC_CCR = TC_CLKEN ;

    //* Clear the status
    tmp = tc_ptr->TC[0].TC_SR ;
    tmp = tc_ptr->TC[1].TC_SR ;
    tmp = tc_ptr->TC[2].TC_SR ;

    //* Trig Timer2
    tc_ptr->TC[2].TC_CCR = TC_SWTRG ;

    //* Trig Timer1, set TIOA and effective clear timer 2
    tc_ptr->TC[1].TC_CCR = TC_SWTRG ;

}
//*----------------------------------------------------------------------------
//* Function Name       : at91_tc_start
//* Object              :
//* Input Parameters    : <TC_pt>  timer descriptor
//* Output Parameters   :
//*----------------------------------------------------------------------------
void at91_tc_start( const TCBlockDesc *TC_pt )
{
    //* -- Start timer by Software Trigger
    //* Trig Timer0, set TIOA and effective clear timer 1
    TC_pt->tc0_desc->tc_base->TC_CCR = TC_SWTRG ;
}
//*----------------------------------------------------------------------------
//* Function Name       : at91_tc_stop
//* Object              :
//* Input Parameters    : <TC_pt>  timer descriptor
//* Output Parameters   :
//*----------------------------------------------------------------------------
u_int at91_tc_stop( const TCBlockDesc *TC_pt )
{
	u_int mcki;
    StructTCBlock   *tc_ptr = (StructTCBlock *)TC_pt->tc0_desc->tc_base ;

    //* Disable the clock of the Timer Counter channel 0
    TC_pt->tc0_desc->tc_base->TC_CCR = TC_CLKDIS ;

    //* Compute number of microseconds from counter values
    mcki =  tc_ptr->TC[0].TC_CV  ;
    mcki += ( tc_ptr->TC[1].TC_CV * 1000 ) ;
    mcki += ( tc_ptr->TC[2].TC_CV * 1000000 ) ;
    // TIMER CLOCK MCKI / 2
    mcki = mcki*2;

    //* Disable the clock and reset the timer
    // Close the timer
    at91_tc_close (TC_pt->tc0_desc);
    at91_tc_close (TC_pt->tc1_desc);
    at91_tc_close (TC_pt->tc2_desc);

    return mcki;
//* End
}