nemo1991 发表于 2015-4-3 09:31
1.发送中断时28027发送字符才进入的。
2.如果需要接收两位数，你需要设置一个帧头，最好也有桢尾，中间放上你要加的数据。
谢谢！但是针对第一个问题，对于sci_loopback_int的例程还是不太理解，因为主程序中并没有发送字符的语句，那第一次中断是如何进入的呢？
例程代码如下：
#include "DSP28x_Project.h" // Device Headerfile and Examples Include File
#define CPU_FREQ 40E6 // Default = 40 MHz. Change to 60E6 for 60 MHz devices
#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[2]; // Send data for SCI-A
Uint16 rdataA[2]; // Received data for SCI-A
Uint16 rdata_pointA; // Used for checking the received data
void main(void)
{
Uint16 i;
// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the DSP2802x_SysCtrl.c file.
InitSysCtrl();
// Step 2. Initalize GPIO:
// This example function is found in the DSP2802x_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 DSP2802x_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 DSP2802x_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 DSP2802x_DefaultIsr.c.
// This function is found in DSP2802x_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;
EDIS; // This is needed to disable write to EALLOW protected registers
// Step 4. Initialize all the Device Peripherals:
// This function is found in DSP2802x_InitPeripherals.c
// InitPeripherals(); // Not required for this example
scia_fifo_init(); // Init SCI-A
// 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
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