確定在 MPLAB IDE 下沒有重複開啟同一Project?
如果沒有的話，就就先關閉所有的 Project 後在重新建立一個新的 Project 看看。

我有一塊DM300027實驗版
裡面有三個範例!
一個是給30F系列使用!
我有30F4012 IC
去跑這範例:
#include "p30F2010.h"
// the above include path may be different for each user. If a compile
// time error appears then check the path for the file above and edit
// the include statement above.

#define XTFREQ 7372800 //On-board Crystal frequency
#define PLLMODE 16 //On-chip PLL setting
#define FCY XTFREQ*PLLMODE/4 //Instruction Cycle Frequency

#define BAUDRATE 9600
#define BRGVAL ((FCY/BAUDRATE)/16)-1


int main(void)
{

ADPCFG = 0xFF; //Make analog pins digital

LATE = 0x0;
TRISE = 0xF0; //Configure LED pins as output

TMR1 = 0; // clear timer 1
PR1 = 0x7270; // interrupt every 250ms
IFS0bits.T1IF = 0; // clr interrupt flag
IEC0bits.T1IE = 1; // set interrupt enable bit
T1CON = 0x8030; // Fosc/4, 1:256 prescale, start TMR1


TRISF = 0xC;
U1BRG = BRGVAL;
U1MODE = 0x8000; // Reset UART to 8-n-1, alt pins, and enable
U1STA = 0x0440; // Reset status register and enable TX & RX


_U1RXIF=0; // Clear UART RX Interrupt Flag


while(1)
{
int a;

while (_U1RXIF==0); // Wait and receive one Character
a = U1RXREG;

while(!U1STAbits.TRMT); // Echo back received character with quotes
U1TXREG = '"';

while(!U1STAbits.TRMT);
U1TXREG = a;

while(!U1STAbits.TRMT);
U1TXREG = '"';

while(!U1STAbits.TRMT);
U1TXREG = ' ';

_U1RXIF=0; // Clear UART RX Interrupt Flag

}
return 0;
}


void __attribute__((interrupt, no_auto_psv)) _T1Interrupt(void)
{
IFS0bits.T1IF = 0; // clear interrupt flag

LATE ^= 0xF; //Toggle LED's
}


開專案有一個檔名LED.mcp
但是都出現 LED.mcp is already open.
為何??