关于scia_loopback_interrupt中断问题

eworldlz · 发表于2015-12-23 16:45

关于scia_loopback_interrupt中断问题 [复制链接]

我是新手，在看scia_loopback_interrupt例程，不应该是先把要发送的数据写到SCITXBUF里，才会触发中断吗，为什么SciaRegs.SCITXBUF=sdataA[i]；这个就在中断里，那他是如何进入中断的，求各位大神指教，困扰好久了

eworldlz · 发表于2015-12-23 16:56

#include "DSP28x_Project.h" // Device Headerfile and Examples Include File
#define CPU_FREQ 150E6
#define LSPCLK_FREQ CPU_FREQ/4
#define SCI_FREQ 100E3
#define SCI_PRD (LSPCLK_FREQ/(SCI_FREQ*8))-1
// Prototype statements for functions found within this file.
interrupt void sciaTxFifoIsr(void);
interrupt void sciaRxFifoIsr(void);
interrupt void scibTxFifoIsr(void);
interrupt void scibRxFifoIsr(void);
void scia_fifo_init(void);
void scib_fifo_init(void);
void error(void);
// Global variables
Uint16 sdataA[8]; // Send data for SCI-A
Uint16 sdataB[8]; // Send data for SCI-B
Uint16 rdataA[8]; // Received data for SCI-A
Uint16 rdataB[8]; // Received data for SCI-A
Uint16 rdata_pointA; // Used for checking the received data
Uint16 rdata_pointB;
void main(void)
{
Uint16 i;
// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the DSP2833x_SysCtrl.c file.
InitSysCtrl();
// Step 2. Initalize 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();
// Setup only the GP I/O only for SCI-A and SCI-B functionality
// This function is found in DSP2833x_Sci.c
InitSciGpio();
// 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.SCIRXINTA = &sciaRxFifoIsr;
PieVectTable.SCITXINTA = &sciaTxFifoIsr;
PieVectTable.SCIRXINTB = &scibRxFifoIsr;
PieVectTable.SCITXINTB = &scibTxFifoIsr;
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
scia_fifo_init(); // Init SCI-A
scib_fifo_init(); // Init SCI-B
// Step 5. User specific code, enable interrupts:
// Init send data. After each transmission this data
// will be updated for the next transmission
for(i = 0; i<8; i++)
{
sdataA[i] = i;
}
for(i = 0; i<8; i++)
{
sdataB[i] = 0xFF - i;
}
rdata_pointA = sdataA[0];
rdata_pointB = sdataB[0];
// Enable interrupts required for this example
PieCtrlRegs.PIECTRL.bit.ENPIE = 1; // Enable the PIE block
PieCtrlRegs.PIEIER9.bit.INTx1=1; // PIE Group 9, int1
PieCtrlRegs.PIEIER9.bit.INTx2=1; // PIE Group 9, INT2
PieCtrlRegs.PIEIER9.bit.INTx3=1; // PIE Group 9, INT3
PieCtrlRegs.PIEIER9.bit.INTx4=1; // PIE Group 9, INT4
IER = 0x100; // Enable CPU INT
EINT;
// Step 6. IDLE loop. Just sit and loop forever (optional):
for(;;);
}
void error(void)
{
asm(" ESTOP0"); // Test failed!! Stop!
for (;;);
}
interrupt void sciaTxFifoIsr(void)
{
Uint16 i;
for(i=0; i< 8; i++)
{
SciaRegs.SCITXBUF=sdataA[i]; // Send data
}
/*for(i=0; i< 8; i++) //Increment send data for next cycle
{
sdataA[i] = (sdataA[i]+1) & 0x00FF;
}*/
SciaRegs.SCIFFTX.bit.TXFFINTCLR=1; // Clear SCI Interrupt flag
PieCtrlRegs.PIEACK.all|=0x100; // Issue PIE ACK
}
interrupt void sciaRxFifoIsr(void)
{
Uint16 i;
for(i=0;i<8;i++)
{
rdataA[i]=SciaRegs.SCIRXBUF.all; // Read data
}
/*for(i=0;i<8;i++) // Check received data
{
if(rdataA[i] != ( (rdata_pointA+i) & 0x00FF) ) error();
}
rdata_pointA = (rdata_pointA+1) & 0x00FF;*/
SciaRegs.SCIFFRX.bit.RXFFOVRCLR=1; // Clear Overflow flag
SciaRegs.SCIFFRX.bit.RXFFINTCLR=1; // Clear Interrupt flag
PieCtrlRegs.PIEACK.all|=0x100; // Issue PIE ack
}
void scia_fifo_init()
{
SciaRegs.SCICCR.all =0x0007; // 1 stop bit, No loopback
// No parity,8 char bits,
// async mode, idle-line protocol
SciaRegs.SCICTL1.all =0x0003; // enable TX, RX, internal SCICLK,
// Disable RX ERR, SLEEP, TXWAKE
SciaRegs.SCICTL2.bit.TXINTENA =1;
SciaRegs.SCICTL2.bit.RXBKINTENA =1;
SciaRegs.SCIHBAUD = 0x0000;
SciaRegs.SCILBAUD = SCI_PRD;
SciaRegs.SCICCR.bit.LOOPBKENA =1; // Enable loop back
SciaRegs.SCIFFTX.all=0xC028;
SciaRegs.SCIFFRX.all=0x0028;
SciaRegs.SCIFFCT.all=0x00;
SciaRegs.SCICTL1.all =0x0023; // Relinquish SCI from Reset
SciaRegs.SCIFFTX.bit.TXFIFOXRESET=1;
SciaRegs.SCIFFRX.bit.RXFIFORESET=1;
}
interrupt void scibTxFifoIsr(void)
{
Uint16 i;
for(i=0; i< 8; i++)
{
ScibRegs.SCITXBUF=sdataB[i]; // Send data
}
for(i=0; i< 8; i++) //Increment send data for next cycle
{
sdataB[i] = (sdataB[i]-1) & 0x00FF;
}
ScibRegs.SCIFFTX.bit.TXFFINTCLR=1; // Clear Interrupt flag
PieCtrlRegs.PIEACK.all|=0x100; // Issue PIE ACK
}
interrupt void scibRxFifoIsr(void)
{
Uint16 i;
for(i=0;i<8;i++)
{
rdataB[i]=ScibRegs.SCIRXBUF.all; // Read data
}
for(i=0;i<8;i++) // Check received data
{
if(rdataB[i] != ( (rdata_pointB-i) & 0x00FF) ) error();
}
rdata_pointB = (rdata_pointB-1) & 0x00FF;
ScibRegs.SCIFFRX.bit.RXFFOVRCLR=1; // Clear Overflow flag
ScibRegs.SCIFFRX.bit.RXFFINTCLR=1; // Clear Interrupt flag
PieCtrlRegs.PIEACK.all|=0x100; // Issue PIE ack
}
void scib_fifo_init()
{
ScibRegs.SCICCR.all =0x0007; // 1 stop bit, No loopback
// No parity,8 char bits,
// async mode, idle-line protocol
ScibRegs.SCICTL1.all =0x0003; // enable TX, RX, internal SCICLK,
// Disable RX ERR, SLEEP, TXWAKE
ScibRegs.SCICTL2.bit.TXINTENA =1;
ScibRegs.SCICTL2.bit.RXBKINTENA =1;
ScibRegs.SCIHBAUD =0x0000;
ScibRegs.SCILBAUD =SCI_PRD;
ScibRegs.SCICCR.bit.LOOPBKENA =1; // Enable loop back
ScibRegs.SCIFFTX.all=0xC028;
ScibRegs.SCIFFRX.all=0x0028;
ScibRegs.SCIFFCT.all=0x00;
ScibRegs.SCICTL1.all =0x0023; // Relinquish SCI from Reset
ScibRegs.SCIFFTX.bit.TXFIFOXRESET=1;
ScibRegs.SCIFFRX.bit.RXFIFORESET=1;
}
//===========================================================================
// No more.
//===========================================================================

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这是例程看到有人说通过TXRDY标志位引发中断，但是给SCIRXBUF和SCITXBUF赋值都是在中断里啊，那第一次是怎么进入中断的呢求大神解答

eworldlz · 发表于2015-12-23 16:58

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