ATmega328p Xplained Mini 串口发送数据

ddllxxrr

这个小板首先得搞清楚工作的晶振，我始终糊涂，我一直以为8MRC内部振荡，今天打开图纸一看才恍然大悟。

原来是16M外部晶振，同时给两个芯片。我晕！！！
解决完晶振问题自然是寄存器，同发射有关的寄存器如下：
UCSRnA
BIT7 - RXCn:usart Receive Complete
BIT6 - TXCn:USART Transmit Complete
Bit5 - UDREn:USART Data Register Empty
Bit4 - FEn:Frame Error
Bit3 - DORnata OverRun
Bit2 - UPEn:USART Parity Error
Bit1 - U2Xnouble the USART Transmission Speed
Bit0 - MPCMn:Mutlti-processor Communication Mode
UCSRnB
Bit7 - RXCIEn:RX Complete Interrupt Enable n
Bit6 - TXCIEn:TX Complete Interrupt Enable n
Bit5 - UDRIEn:USART Data Register Empty Interrupt Enable n
Bit4 - RXENn:Receiver Enable n
Bit3 - TXENn:Transmitter Enable n
Bit2 - UCSZn2:Character Size n
Bit1 - RXB8n:Receive Data Bit 8n
Bit0 - TXB8n:Transmit Data Bit8n
UCSRnC
Bits 7:6 - UMSELn1:0 USART Mode Select
           00异步
           01同步
           10空
           11SPI
Bits 5:4 - UPMn1:0arity Mode
Bit3     - USBSn:Stop Bit Select
Bit2:1   - UCSZn1:0:Character Size
Bit 0    - UCPOLn:Clock Polarity
这里边只有掌握几个位就行：
以下是程序：
/*
* GccApplication2.c
*
* Created: 2015/1/8 星期四 21:20:24
*  Author: Administrator
*/
#define F_CPU 16000000UL
#define BAUD 9600
#define PUTBAUD F_CPU/16/BAUD-1
#include <avr/io.h>
#include <stdio.h>
#include <stdint.h>
#include <util/delay.h>
char dd[]="Hello eeboard!!!";
void Init_USART(uint16_t ubrr)
{
/*Set baud rate */
UBRR0H = (unsigned char)(ubrr>>8);
UBRR0L = (unsigned char)ubrr;
/*Enable receiver and transmitter */
UCSR0B = (1<<RXEN0)|(1<<TXEN0);
/* Set frame format: 8data, 2stop bit */
UCSR0C = (1<<USBS0)|(3<<UCSZ00);
}
void PutChar(char c)
{
/* Wait for empty transmit buffer */
while ( !( UCSR0A & (1<<UDRE0)) )
;
/* Put data into buffer, sends the data */
UDR0 = c;
}
void PutStr(char *s)
{
while(*s)PutChar(*s++);
}
int main(void)
{
Init_USART( PUTBAUD);
while(1)
{
PutStr(dd);
_delay_ms(1000);
//TODO:: Please write your application code
}
}