[讨论] 关于28335Control Suite的External Interrupt的问题

LZt 2016-8-26 09:11 楼主

我在阅读control suite中28335例程（v141）时对下面这个input qualification的delay_us函数产生了疑惑：

1. 为什么设置等待qual周期的时间是35.700us？我跟据reference guide中算出来的，最多只是5*tw（sp）+tw（sp）+Tsysclkout=6*2*255*6.667ns+6.667ns=20.41us？

2. 为什么等待qualification要设置在GPIO31触发GPIO1之前？例程中不是设置GPIO1为滤波采样，所以应该在GPIO31触发GPIO1之后设置延时函数。

#include "DSP28x_Project.h" // Device Headerfile and Examples Include File
// Prototype statements for functions found within this file.
__interrupt void xint1_isr(void);
__interrupt void xint2_isr(void);
// Global variables for this example
volatile Uint32 Xint1Count; //volatile 关键字告诉编译器该变量是随时可能发生变化的，每次使用它的时候必须从内存
//中取出他的值，因而编译器生成的汇编代码会从原内存地址中读取数据使用。
volatile Uint32 Xint2Count;
Uint32 LoopCount;
#define DELAY 35.700L //数字+L代表这是一个long double类型的数值。
void main(void)
{
Uint32 TempX1Count;
Uint32 TempX2Count;
// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the DSP2833x_SysCtrl.c file.
InitSysCtrl();
// Step 2. Initialize GPIO:
// This example function is found in the DSP2833x_Gpio.c file and
// illustrates how to set the GPIO to it's default state.
// InitGpio(); // Skipped for this example
// Step 3. Clear all interrupts and initialize PIE vector table:
// Disable CPU interrupts
DINT;
// Initialize PIE control registers to their default state.
// The default state is all PIE interrupts disabled and flags
// are cleared.
// This function is found in the DSP2833x_PieCtrl.c file.
InitPieCtrl();
// Disable CPU interrupts and clear all CPU interrupt flags:
IER = 0x0000;
IFR = 0x0000;
// Initialize the PIE vector table with pointers to the shell Interrupt
// Service Routines (ISR).
// This will populate the entire table, even if the interrupt
// is not used in this example. This is useful for debug purposes.
// The shell ISR routines are found in DSP2833x_DefaultIsr.c.
// This function is found in DSP2833x_PieVect.c.
InitPieVectTable();
// Interrupts that are used in this example are re-mapped to
// ISR functions found within this file.
EALLOW; // This is needed to write to EALLOW protected registers
PieVectTable.XINT1 = &xint1_isr;
PieVectTable.XINT2 = &xint2_isr;
EDIS; // This is needed to disable write to EALLOW protected registers
// Step 4. Initialize all the Device Peripherals:
// This function is found in DSP2833x_InitPeripherals.c
// InitPeripherals(); // Not required for this example
// Step 5. User specific code, enable interrupts:
// Clear the counters
Xint1Count = 0; // Count Xint1 interrupts
Xint2Count = 0; // Count XINT2 interrupts
LoopCount = 0; // Count times through idle loop
// Enable Xint1 and XINT2 in the PIE: Group 1 interrupt 4 & 5
// Enable int1 which is connected to WAKEINT:
PieCtrlRegs.PIECTRL.bit.ENPIE = 1; // Enable the PIE block
PieCtrlRegs.PIEIER1.bit.INTx4 = 1; // Enable PIE Gropu 1 INT4
PieCtrlRegs.PIEIER1.bit.INTx5 = 1; // Enable PIE Gropu 1 INT5
IER |= M_INT1; // Enable CPU int1
EINT; // Enable Global Interrupts
// GPIO30 & GPIO31 are outputs, start GPIO30 high and GPIO31 low
EALLOW;
GpioDataRegs.GPASET.bit.GPIO30 = 1; // Load the output latch
GpioCtrlRegs.GPAMUX2.bit.GPIO30 = 0; // GPIO
GpioCtrlRegs.GPADIR.bit.GPIO30 = 1; // output
GpioDataRegs.GPACLEAR.bit.GPIO31 = 1; // Load the output latch
GpioCtrlRegs.GPAMUX2.bit.GPIO31 = 0; // GPIO
GpioCtrlRegs.GPADIR.bit.GPIO31 = 1; // output
EDIS;
// GPIO0 and GPIO1 are inputs
EALLOW;
GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 0; // GPIO
GpioCtrlRegs.GPADIR.bit.GPIO0 = 0; // input
GpioCtrlRegs.GPAQSEL1.bit.GPIO0 = 0; // Xint1 Synch to SYSCLKOUT only
GpioCtrlRegs.GPAMUX1.bit.GPIO1 = 0; // GPIO
GpioCtrlRegs.GPADIR.bit.GPIO1 = 0; // input
GpioCtrlRegs.GPAQSEL1.bit.GPIO1 = 2; // XINT2 Qual using 6 samples
GpioCtrlRegs.GPACTRL.bit.QUALPRD0 = 0xFF; // Each sampling window is 510*SYSCLKOUT
EDIS;
// GPIO0 is XINT1, GPIO1 is XINT2
EALLOW;
GpioIntRegs.GPIOXINT1SEL.bit.GPIOSEL = 0; // Xint1 is GPIO0
GpioIntRegs.GPIOXINT2SEL.bit.GPIOSEL = 1; // XINT2 is GPIO1
EDIS;
// Configure XINT1
XIntruptRegs.XINT1CR.bit.POLARITY = 0; // Falling edge interrupt
XIntruptRegs.XINT2CR.bit.POLARITY = 1; // Rising edge interrupt
// Enable XINT1 and XINT2
XIntruptRegs.XINT1CR.bit.ENABLE = 1; // Enable Xint1
XIntruptRegs.XINT2CR.bit.ENABLE = 1; // Enable XINT2
// GPIO34 will go low inside each interrupt. Monitor this on a scope
EALLOW;
GpioCtrlRegs.GPBMUX1.bit.GPIO34 = 0; // GPIO
GpioCtrlRegs.GPBDIR.bit.GPIO34 = 1; // output
EDIS;
// Step 6. IDLE loop:
for(;;)
{
TempX1Count = Xint1Count;
TempX2Count = Xint2Count;
// Trigger both XINT1
GpioDataRegs.GPBSET.bit.GPIO34 = 1; // GPIO34 is high
GpioDataRegs.GPACLEAR.bit.GPIO30 = 1; // Lower GPIO30, trigger Xint1
while(Xint1Count == TempX1Count) {}
// Trigger both XINT2
GpioDataRegs.GPBSET.bit.GPIO34 = 1; // GPIO34 is high
DELAY_US(DELAY); // Wait for Qual period
GpioDataRegs.GPASET.bit.GPIO31 = 1; // Raise GPIO31, trigger XINT2
while(Xint2Count == TempX2Count) {}
// Check that the counts were incremented properly and get ready
// to start over.
if(Xint1Count == TempX1Count+1 && Xint2Count == TempX2Count+1)
{
LoopCount++;
GpioDataRegs.GPASET.bit.GPIO30 = 1; // raise GPIO30
GpioDataRegs.GPACLEAR.bit.GPIO31 = 1; // lower GPIO31
}
else
{
__asm(" ESTOP0"); // stop here 注释见文档下方
}
}
}
// Step 7. Insert all local Interrupt Service Routines (ISRs) and functions here:
// If local ISRs are used, reassign vector addresses in vector table as
// shown in Step 5
__interrupt void xint1_isr(void)
{
GpioDataRegs.GPBCLEAR.all = 0x4; // GPIO34 is low
Xint1Count++;
// Acknowledge this interrupt to get more from group 1
PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;
}
__interrupt void xint2_isr(void)
{
GpioDataRegs.GPBCLEAR.all = 0x4; // GPIO34 is low
Xint2Count++;
// Acknowledge this interrupt to get more from group 1
PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;
}
//===========================================================================
// No more.
//===========================================================================

回复评论

暂无评论，赶紧抢沙发吧