EX23 USART

//EX23 TWI master//author :dave//data:2018.4.23//EX23和EX24配合起来实现一主一从的通讯//主发一个数据从接受并显示出来//然后从将该数据反过来发送给主，主显示出来#include#include

#define uchar unsigned char

#define uint unsigned int

#define start 0x08

#define re_start 0x10

#define m_arbitration_lost 0x38

//MT

#define mt_sla_ack 0x18

#define mt_sla_nack 0x20

#define mt_data_ack 0x28

#define mt_data_nack 0x30

//MR

#define mr_sla_ack 0x40

#define mr_sla_nack 0x48

#define mr_data_ack 0x50

#define mr_data_nack 0x58

#define START(); {TWCR =(1<