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// TI File $Revision: /main/4 $
// Checkin $Date: July 2, 2007 11:27:41 $
//###########################################################################
//
// FILE: Example_281xSpi_FFDLB_int.c
//
// TITLE: DSP281x Device Spi Digital Loop Back porgram.
//
// ASSUMPTIONS:
//
// This program requires the DSP281x V1.00 header files.
// As supplied, this project is configured for "boot to H0" operation.
//
// Other then boot mode pin configuration, no other hardware configuration
// is required.
//
// DESCRIPTION:
//
// This program is a SPI example that uses the internal loopback of
// the peripheral. Both interrupts and the SPI FIFOs are used.
//
// A stream of data is sent and then compared to the recieved stream.
//
// The sent data looks like this:
// 0000 0001 0002 0003 0004 0005 0006 0007
// 0001 0002 0003 0004 0005 0006 0007 0008
// 0002 0003 0004 0005 0006 0007 0008 0009
// ....
// FFFE FFFF 0000 0001 0002 0003 0004 0005
// FFFF 0000 0001 0002 0003 0004 0005 0006
// etc..
//
// This pattern is repeated forever.
//
//
// Watch Variables:
// sdata[8] - Data to send
// rdata[8] - Received data
// rdata_point - Used to keep track of the last position in
// the receive stream for error checking
//###########################################################################
// $TI Release: DSP281x C/C++ Header Files V1.20 $
// $Release Date: July 27, 2009 $
//###########################################################################
#include "DSP281x_Device.h" // DSP281x Headerfile Include File
#include "DSP281x_Examples.h" // DSP281x Examples Include File
// Prototype statements for functions found within this file.
// interrupt void ISRTimer2(void);
interrupt void spiTxFifoIsr(void);
interrupt void spiRxFifoIsr(void);
void delay_loop(void);
void spi_fifo_init(void);
void error();
Uint16 sdata[8]; // Send data buffer
Uint16 rdata[8]; // Receive data buffer
Uint16 rdata_point; // Keep track of where we are
// in the data stream to check received data
void main(void)
{
Uint16 i;
// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the DSP281x_SysCtrl.c file.
InitSysCtrl();
// Step 2. Initalize GPIO:
// This example function is found in the DSP281x_Gpio.c file and
// illustrates how to set the GPIO to it's default state.
// InitGpio(); // Skipped for this example
// Setup only the GP I/O only for SPI functionality
EALLOW;
GpioMuxRegs.GPFMUX.all=0x000F; // Select GPIOs to be SPI pins
// Port F MUX - x000 0000 0000 1111
EDIS;
// Step 3. Initialize PIE vector table:
// Disable and clear all CPU interrupts
DINT;
IER = 0x0000;
IFR = 0x0000;
// Initialize PIE control registers to their default state:
// This function is found in the DSP281x_PieCtrl.c file.
InitPieCtrl();
// 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 DSP281x_DefaultIsr.c.
// This function is found in DSP281x_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.SPIRXINTA = &spiRxFifoIsr;
PieVectTable.SPITXINTA = &spiTxFifoIsr;
EDIS; // This is needed to disable write to EALLOW protected registers
// Step 4. Initialize all the Device Peripherals:
// This function is found in DSP281x_InitPeripherals.c
// InitPeripherals(); // Not required for this example
spi_fifo_init(); // Initialize the SPI only
// Step 5. User specific code, enable interrupts:
// Initalize the send data buffer
for(i=0; i<8; i++)
{
sdata = i;
}
rdata_point = 0;
// Enable interrupts required for this example
PieCtrlRegs.PIECRTL.bit.ENPIE = 1; // Enable the PIE block
PieCtrlRegs.PIEIER6.bit.INTx2=1; // Enable PIE Group 6, INT 2
PieCtrlRegs.PIEIER6.bit.INTx1=1; // Enable PIE Group 6, INT 1
IER=0x20; // Enable CPU INT6
EINT; // Enable Global Interrupts
// Step 6. IDLE loop. Just sit and loop forever (optional):
for(;;);
}
// Some Useful local functions
void delay_loop()
{
long i;
for (i = 0; i < 1000000; i++) {}
}
void error(void)
{
asm(" ESTOP0"); //Test failed!! Stop!
for (;;);
}
void spi_fifo_init()
{
// Initialize SPI FIFO registers
SpiaRegs.SPICCR.bit.SPISWRESET=0; // Reset SPI
SpiaRegs.SPICCR.all=0x001F; //16-bit character, Loopback mode
SpiaRegs.SPICTL.all=0x0016; //Interrupt enabled, Master/Slave XMIT enabled
SpiaRegs.SPISTS.all=0x0000;
SpiaRegs.SPIBRR=0x0063; // Baud rate
SpiaRegs.SPIFFTX.all=0xC028; // Enable FIFO's, set TX FIFO level to 8
SpiaRegs.SPIFFRX.all=0x0028; // Set RX FIFO level to 8
SpiaRegs.SPIFFCT.all=0x00;
SpiaRegs.SPIPRI.all=0x0010;
SpiaRegs.SPICCR.bit.SPISWRESET=1; // Enable SPI
SpiaRegs.SPIFFTX.bit.TXFIFO=1;
SpiaRegs.SPIFFRX.bit.RXFIFORESET=1;
}
interrupt void spiTxFifoIsr(void)
{
Uint16 i;
for(i=0;i<8;i++)
{
SpiaRegs.SPITXBUF=sdata; // Send data
}
for(i=0;i<8;i++) // Increment data for next cycle
{
sdata++;
}
SpiaRegs.SPIFFTX.bit.TXFFINTCLR=1; // Clear Interrupt flag
PieCtrlRegs.PIEACK.all|=0x20; // Issue PIE ACK
}
interrupt void spiRxFifoIsr(void)
{
Uint16 i;
for(i=0;i<8;i++)
{
rdata=SpiaRegs.SPIRXBUF; // Read data
}
for(i=0;i<8;i++) // Check received data
{
if(rdata != rdata_point+i) error();
}
rdata_point++;
SpiaRegs.SPIFFRX.bit.RXFFOVFCLR=1; // Clear Overflow flag
SpiaRegs.SPIFFRX.bit.RXFFINTCLR=1; // Clear Interrupt flag
PieCtrlRegs.PIEACK.all|=0x20; // Issue PIE ack
}
//===========================================================================
// No more.
//===========================================================================
如题，我的疑问是，程序在主函数里面又没有向发送缓冲区里面写数据，怎么能触发中断呢？我个人觉得是不是因为这里将发送的中断级别为设置为8，而此时的状态为0，小于8，所以触发中断？
但是我经过测试确实可以进入中断，不知道理解对不对，请求指导一下。。 |
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