请马潮老师帮我解答一下
我在使用ATmega128的第二个串口时，此串口总接受不到数据，我看书上说：RXD1为USART1数据接收引脚,当使能USART1接收器,强制设置为输出,此时DDD2不起作用,但PORTD2仍然控制上拉电阻,现在我此串口接受不到数据,怎样设置寄存器，请您指点指点,谢谢 #include <mega128.h>#define RXB8 1
#define TXB8 0
#define UPE 2
#define OVR 3
#define FE 4
#define UDRE 5
#define RXC 7
#define FRAMING_ERROR (1<<FE)
#define PARITY_ERROR (1<<UPE)
#define DATA_OVERRUN (1<<OVR)
#define DATA_REGISTER_EMPTY (1<<UDRE)
#define RX_COMPLETE (1<<RXC)
// USART1 Receiver buffer
#define RX_BUFFER_SIZE1 8
char rx_buffer1;
#if RX_BUFFER_SIZE1<256
unsigned char rx_wr_index1,rx_rd_index1,rx_counter1;
#else
unsigned int rx_wr_index1,rx_rd_index1,rx_counter1;
#endif
// This flag is set on USART1 Receiver buffer overflow
bit rx_buffer_overflow1;
// USART1 Receiver interrupt service routine
interrupt void usart1_rx_isr(void)
{
char status,data;
status=UCSR1A;
data=UDR1;
if ((status & (FRAMING_ERROR | PARITY_ERROR | DATA_OVERRUN))==0)
{
rx_buffer1=data;
if (++rx_wr_index1 == RX_BUFFER_SIZE1) rx_wr_index1=0;
if (++rx_counter1 == RX_BUFFER_SIZE1)
{
rx_counter1=0;
rx_buffer_overflow1=1;
};
};
}
// Get a character from the USART1 Receiver buffer
#pragma used+
char getchar1(void)
{
char data;
while (rx_counter1==0);
data=rx_buffer1;
if (++rx_rd_index1 == RX_BUFFER_SIZE1) rx_rd_index1=0;
#asm("cli")
--rx_counter1;
#asm("sei")
return data;
}
#pragma used-
// USART1 Transmitter buffer
#define TX_BUFFER_SIZE1 8
char tx_buffer1;
#if TX_BUFFER_SIZE1<256
unsigned char tx_wr_index1,tx_rd_index1,tx_counter1;
#else
unsigned int tx_wr_index1,tx_rd_index1,tx_counter1;
#endif
// USART1 Transmitter interrupt service routine
interrupt void usart1_tx_isr(void)
{
if (tx_counter1)
{
--tx_counter1;
UDR1=tx_buffer1;
if (++tx_rd_index1 == TX_BUFFER_SIZE1) tx_rd_index1=0;
};
}
// Write a character to the USART1 Transmitter buffer
#pragma used+
void putchar1(char c)
{
while (tx_counter1 == TX_BUFFER_SIZE1);
#asm("cli")
if (tx_counter1 || ((UCSR1A & DATA_REGISTER_EMPTY)==0))
{
tx_buffer1=c;
if (++tx_wr_index1 == TX_BUFFER_SIZE1) tx_wr_index1=0;
++tx_counter1;
}
else
UDR1=c;
#asm("sei")
}
#pragma used-
// Declare your global variables here
void main(void)
{
// Declare your local variables here
// Input/Output Ports initialization
// Port A initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T
PORTA=0x00;
DDRA=0x00;
// Port B initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T
PORTB=0x00;
DDRB=0x00;
// Port C initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T
PORTC=0x00;
DDRC=0x00;
// Port D initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T
PORTD=0x00;
DDRD=0x00;
// Port E initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T
PORTE=0x00;
DDRE=0x00;
// Port F initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T
PORTF=0x00;
DDRF=0x00;
// Port G initialization
// Func4=In Func3=In Func2=In Func1=In Func0=In
// State4=T State3=T State2=T State1=T State0=T
PORTG=0x00;
DDRG=0x00;
// Timer/Counter 0 initialization
// Clock source: System Clock
// Clock value: Timer 0 Stopped
// Mode: Normal top=FFh
// OC0 output: Disconnected
ASSR=0x00;
TCCR0=0x00;
TCNT0=0x00;
OCR0=0x00;
// Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: Timer 1 Stopped
// Mode: Normal top=FFFFh
// OC1A output: Discon.
// OC1B output: Discon.
// OC1C output: Discon.
// Noise Canceler: Off
// Input Capture on Falling Edge
// Timer 1 Overflow Interrupt: Off
// Input Capture Interrupt: Off
// Compare A Match Interrupt: Off
// Compare B Match Interrupt: Off
// Compare C Match Interrupt: Off
TCCR1A=0x00;
TCCR1B=0x00;
TCNT1H=0x00;
TCNT1L=0x00;
ICR1H=0x00;
ICR1L=0x00;
OCR1AH=0x00;
OCR1AL=0x00;
OCR1BH=0x00;
OCR1BL=0x00;
OCR1CH=0x00;
OCR1CL=0x00;
// Timer/Counter 2 initialization
// Clock source: System Clock
// Clock value: Timer 2 Stopped
// Mode: Normal top=FFh
// OC2 output: Disconnected
TCCR2=0x00;
TCNT2=0x00;
OCR2=0x00;
// Timer/Counter 3 initialization
// Clock source: System Clock
// Clock value: Timer 3 Stopped
// Mode: Normal top=FFFFh
// Noise Canceler: Off
// Input Capture on Falling Edge
// OC3A output: Discon.
// OC3B output: Discon.
// OC3C output: Discon.
// Timer 3 Overflow Interrupt: Off
// Input Capture Interrupt: Off
// Compare A Match Interrupt: Off
// Compare B Match Interrupt: Off
// Compare C Match Interrupt: Off
TCCR3A=0x00;
TCCR3B=0x00;
TCNT3H=0x00;
TCNT3L=0x00;
ICR3H=0x00;
ICR3L=0x00;
OCR3AH=0x00;
OCR3AL=0x00;
OCR3BH=0x00;
OCR3BL=0x00;
OCR3CH=0x00;
OCR3CL=0x00;
// External Interrupt(s) initialization
// INT0: Off
// INT1: Off
// INT2: Off
// INT3: Off
// INT4: Off
// INT5: Off
// INT6: Off
// INT7: Off
EICRA=0x00;
EICRB=0x00;
EIMSK=0x00;
// Timer(s)/Counter(s) Interrupt(s) initialization
TIMSK=0x00;
ETIMSK=0x00;
// USART1 initialization
// Communication Parameters: 8 Data, 1 Stop, No Parity
// USART1 Receiver: On
// USART1 Transmitter: On
// USART1 Mode: Asynchronous
// USART1 Baud Rate: 9600
UCSR1A=0x00;
UCSR1B=0xD8;
UCSR1C=0x06;
UBRR1H=0x00;
UBRR1L=0x19;
// Analog Comparator initialization
// Analog Comparator: Off
// Analog Comparator Input Capture by Timer/Counter 1: Off
ACSR=0x80;
SFIOR=0x00;
// Global enable interrupts
#asm("sei")
while (1)
{
// Place your code here
};
}
CVAVR中生成的M128 USART1初始化代码,请参考.
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