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/*****************************************************************************/
/**
* @file xttcps_rtc_example.c
*
* This example uses one timer/counter
to make a real time clock.
The number of
* minutes and seconds is displayed on
the console.
*
*
* @note
*
* <pre>
* MODIFICATION HIS
TORY:
*
* Ver Who Date Changes
* ---- ------ -------- ---------------------------------------------
* 1.00 drg/jz 01/23/10 First release
* 3.01 pkp 01/30/16 Modified Set
upTimer
to remove XTtcps_S
top before TTC
* configuration as it is added in xttcps.c in
* XTtcPs_CfgInitialize
* 3.2 mus 10/28/16
Updated TmrCntrSet
up as per pro
totype of
* XTtcPs_CalcIntervalFromFreq
* ms 01/23/17 Modified xil_printf statement in main function
to
* ensure that "
Successfully ran" and "Failed" strings
* are available in all examples. This is a fix for
* CR-96
5028.
*</pre>
******************************************************************************/
/***************************** Include Files *********************************/
#include <stdio.h>
#include <stdlib.h>
#include "xparameters.h"
#include "xstatus.h"
#include "xil_io.h"
#include "xil_exception.h"
#include "xttcps.h"
#include "xscugic.h"
#include "xil_printf.h"
/************************** Constant Definitions *****************************/
/*
*
The following constants map
to the XPAR parameters created in
the
* xparameters.h file.
They are only defined here such that a user can easily
* change all
the needed parameters in one place.
*/
#define TTC_TICK_DEVICE_ID XPAR_XTTCPS_0_DEVICE_ID
#define TTC_TICK_INTR_ID XPAR_XTTCPS_0_INTR
#define INTC_DEVICE_ID XPAR_SCUGIC_SINGLE_DEVICE_ID
/*
* Constants
to set
the basic operating parameters.
* PWM_DELTA_DUTY is
critical to the running time of
the test. Smaller values
* make
the test run longer.
*/
#define TICK_TIMER_FREQ_HZ 100 /* Tick timer counter's output frequency */
#define TICKS_PER_CHANGE_PERIOD TICK_TIMER_FREQ_HZ /* Tick signals per
update */
/**************************** Type Definitions *******************************/
typedef struct {
u32 OutputHz; /* Output frequency */
XInterval Interval; /* Interval value */
u8 Prescaler; /* NO USED */
u16 Options; /* Option settings */
} TmrCntrSet
up;
/***************** Macros (Inline Functions) Definitions *********************/
/************************** Function Pro
totypes ******************************/
static int TmrRtcInterr
uptExample(void); /* Main test */
/* Set
up routines for timer counters */
static int Set
upTicker(void);
static int Set
upTimer(int DeviceID);
/* Interleaved interr
upt test for both timer counters */
static int WaitForDutyCycleFull(void);
static int Set
upInterr
uptSystem(u16 IntcDeviceID, XScuGic *IntcInstancePtr);
static void TickHandler(void *CallBackRef);
/************************** Variable Definitions *****************************/
static XTtcPs TtcPsInst; /* Timer counter instance */
static TmrCntrSet
up SettingsTable=
{TICK_TIMER_FREQ_HZ, 0, 0, 0}; /* Ticker timer counter initial set
up,
only output freq */
XScuGic Interr
uptController; /* Interr
upt controller instance */
static u8 ErrorCount; /* Errors seen at interr
upt time */
static volatile u8
UpdateFlag; /* Flag
to update
the seconds counter */
static u32 TickCount; /* Ticker interr
upts between seconds change */
/*****************************************************************************/
/**
*
* This is
the main function that calls
the TTC RTC interr
upt example.
*
* @param None
*
* @return
* - XST_
SUCCESS to indicate
Success
* - XST_FAILURE
to indicate a Failure.
*
* @note None.
*
*****************************************************************************/
int main(void)
{
int Status;
xil_printf("Starting Timer RTC Example");
Status = TmrRtcInterr
uptExample();
if (Status != XST_
SUCCESS) {
xil_printf("ttcps rtc Example Failed\r\n");
return XST_FAILURE;
}
xil_printf("
Successfully ran ttcps rtc Example\r\n");
return XST_
SUCCESS;
}
/*****************************************************************************/
/**
*
* This is
the main function of
the interr
upt example.
*
*
* @param None.
*
* @return XST_
SUCCESS to indicate
success, else XST_FAILURE
to indicate
* a Failure.
*
****************************************************************************/
static int TmrRtcInterr
uptExample(void)
{
int Status;
/*
* Make sure
the interr
upts are disabled, in case this is being run
* again after a failure.
*/
/*
* Connect
the Intc
to the interr
upt subsystem such that interr
upts can
* occur. This function is application specific.
*/
Status = Set
upInterr
uptSystem(INTC_DEVICE_ID, &Interr
uptController);
if (Status != XST_
SUCCESS) {
return XST_FAILURE;
}
/*
* Set
up the Ticker timer
*/
Status = Set
upTicker();
if (Status != XST_
SUCCESS) {
return Status;
}
Status = WaitForDutyCycleFull();
if (Status != XST_
SUCCESS) {
return Status;
}
/*
* S
top
the counters
*/
XTtcPs_S
top(&TtcPsInst);
return XST_
SUCCESS;
}
/****************************************************************************/
/**
*
* This function sets
up the Ticker timer.
*
* @param None
*
* @return XST_
SUCCESS if everything sets
up well, XST_FAILURE o
therwise.
*
*****************************************************************************/
int Set
upTicker(void)
{
int Status;
TmrCntrSet
up *TimerSet
up;
XTtcPs *TtcPsTick;
TimerSet
up = &SettingsTable;
/*
* Set
up appropriate options for Ticker: interval mode without
* waveform output.
*/
TimerSet
up->Options |= (XTTCPS_OPTION_INTERVAL_MODE);
/*
* Calling
the timer set
up routine
* . initialize device
* . set options
*/
Status = Set
upTimer(TTC_TICK_DEVICE_ID);
if(Status != XST_
SUCCESS) {
return Status;
}
TtcPsTick = &TtcPsInst;
/*
* Connect
to the interr
upt controller
*/
Status = XScuGic_Connect(&Interr
uptController, TTC_TICK_INTR_ID,
(Xil_Interr
uptHandler)TickHandler, (void *)TtcPsTick);
if (Status != XST_
SUCCESS) {
return XST_FAILURE;
}
/*
* Enable
the interr
upt for
the Timer counter
*/
XScuGic_Enable(&Interr
uptController, TTC_TICK_INTR_ID);
/*
* Enable
the interr
upts for
the tick timer/counter
* We only care about
the interval timeout.
*/
XTtcPs_EnableInterr
upts(TtcPsTick, XTTCPS_IXR_INT_ENABLE);
/*
* Start
the tick timer/counter
*/
XTtcPs_Start(TtcPsTick);
return Status;
}
/****************************************************************************/
/**
*
* This function uses
the interr
upt inter-locking between
the ticker timer
* counter and
the waveform output timer counter. When certain amount of
* interr
upts have happened
to the ticker timer counter, a flag,
UpdateFlag,
* is set
to true.
*
*
* @param None
*
* @return XST_
SUCCESS if duty cycle
successfully reaches beyond 100,
* o
therwise XST_FAILURE.
*
*****************************************************************************/
int WaitForDutyCycleFull(void)
{
u32 seconds;
/*
* Initialize some variables used by
the interr
upts and in loops.
*/
ErrorCount = 0;
seconds = 0;
/*
* Loop until two minutes passes.
*/
while (seconds <= 121) {
/*
* If error occurs, disable interr
upts, and exit.
*/
if (0 != ErrorCount) {
return XST_FAILURE;
}
/*
*
The Ticker interr
upt sets a flag for
update.
*/
if (
UpdateFlag) {
/*
* Calculate
the time setting here, not at
the time
*
critical interr
upt level.
*/
seconds++;
UpdateFlag = FALSE;
xil_printf("Time: %d\n\r", seconds);
}
}
return XST_
SUCCESS;
}
/****************************************************************************/
/**
*
* This function sets
up a timer counter device, using
the information in its
* set
up structure.
* . initialize device
* . set options
* . set interval and prescaler value for given output frequency.
*
* @param DeviceID is
the unique ID for
the device.
*
* @return XST_
SUCCESS if
successful, o
therwise XST_FAILURE.
*
*****************************************************************************/
int Set
upTimer(int DeviceID)
{
int Status;
XTtcPs_Config *Config;
XTtcPs *Timer;
TmrCntrSet
up *TimerSet
up;
TimerSet
up = &SettingsTable;
Timer = &TtcPsInst;
/*
* Look
up the configuration based on
the device identifier
*/
Config = XTtcPs_Look
upConfig(DeviceID);
if (NULL == Config) {
return XST_FAILURE;
}
/*
* Initialize
the device
*/
Status = XTtcPs_CfgInitialize(Timer, Config, Config->BaseAddress);
if (Status != XST_
SUCCESS) {
return XST_FAILURE;
}
/*
* Set
the options
*/
XTtcPs_Se
tOptions(Timer, TimerSet
up->Options);
/*
* Timer frequency is preset in
the TimerSet
up structure,
* however,
the value is not reflected in its o
ther fields, such as
* IntervalValue and PrescalerValue.
The following call will map
the
* frequency
to the interval and prescaler values.
*/
XTtcPs_CalcIntervalFromFreq(Timer, TimerSet
up->OutputHz,
&(TimerSet
up->Interval), &(TimerSet
up->Prescaler));
/*
* Set
the interval and prescale
*/
XTtcPs_SetInterval(Timer, TimerSet
up->Interval);
return XST_
SUCCESS;
}
/****************************************************************************/
/**
*
* This function set
ups
the interr
upt system such that interr
upts can occur.
* This function is application specific since
the actual system may or may not
* have an interr
upt controller.
The TTC could be directly connected
to a
* processor without an interr
upt controller.
The user should modify this
* function
to fit
the application.
*
* @param IntcDeviceID is
the unique ID of
the interr
upt controller
* @param IntcInstacePtr is a pointer
to the interr
upt controller
* instance.
*
* @return XST_
SUCCESS if
successful, o
therwise XST_FAILURE.
*
*****************************************************************************/
static int Set
upInterr
uptSystem(u16 IntcDeviceID,
XScuGic *IntcInstancePtr)
{
int Status;
XScuGic_Config *IntcConfig; /*
The configuration parameters of
the
interr
upt controller */
/*
* Initialize
the interr
upt controller driver
*/
IntcConfig = XScuGic_Look
upConfig(IntcDeviceID);
if (NULL == IntcConfig) {
return XST_FAILURE;
}
Status = XScuGic_CfgInitialize(IntcInstancePtr, IntcConfig,
IntcConfig->CpuBaseAddress);
if (Status != XST_
SUCCESS) {
return XST_FAILURE;
}
/*
* Connect
the interr
upt controller interr
upt handler
to the hardware
* interr
upt handling logic in
the ARM processor.
*/
Xil_ExceptionRegisterHandler(XIL_EXCEPTION_ID_IRQ_INT,
(Xil_ExceptionHandler) XScuGic_Interr
uptHandler,
IntcInstancePtr);
/*
* Enable interr
upts in
the ARM
*/
Xil_ExceptionEnable();
return XST_
SUCCESS;
}
/***************************************************************************/
/**
*
* This function is
the handler which handles
the periodic tick interr
upt.
* It
updates its count, and set a flag
to signal PWM timer counter
to
*
update its duty cycle.
*
* This handler provides an example of how
to handle data for
the TTC and
* is application specific.
*
* @param CallBackRef contains a callback reference from
the driver, in
* this case it is
the instance pointer for
the TTC driver.
*
* @return None.
*
*****************************************************************************/
static void TickHandler(void *CallBackRef)
{
u32 StatusEvent;
/*
* Read
the interr
upt status,
then write it back
to clear
the interr
upt.
*/
StatusEvent = XTtcPs_GetInterr
uptStatus((XTtcPs *)CallBackRef);
XTtcPs_ClearInterr
uptStatus((XTtcPs *)CallBackRef, StatusEvent);
if (0 != (XTTCPS_IXR_INT_ENABLE & StatusEvent)) {
TickCount++;
if (TICKS_PER_CHANGE_PERIOD == TickCount) {
TickCount = 0;
UpdateFlag = TRUE;
}
}
else {
/*
*
The Interval event should be
the only one enabled. If it is
* not it is an error
*/
ErrorCount++;
}
}
请详细分析一下以上的代码，并给出详细的解释
本文阐述了通往成功的五个关键步骤：欲望是动力之源，现身是实现目标的必要条件，面对失败并从中学到经验，付出额外的努力，并享受追求梦想的过程。成功不仅仅是终点，更是旅途中的快乐。
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