1、写操作中有这样一段话：After a restart, the value of the register defined by the command byte matches the register being accessed when the restart occurred. For example, if the command byte references Input Port 1 before the restart, the restart occurs when Input Port 0 is being read. The original command byte is forgotten. If a subsequent restart occurs,Input Port 0 is read first. Data is clocked into the register on the rising edge of the ACK clock pulse. After the first byte is read, additional bytes may be read, but the data now reflect the information in the other register in the pair. For example, if Input Port 1 is read, the next byte read is Input Port 0.
我的疑问：在Restart信号发生时怎么就开始执行读操作，不应该是在主机发送 Restart信号+从机地址 之后才开始执行读操作吗？而且应该是从命令字节所对应的寄存器开始读取数据？
2、数据资料上说刚上电时所有引脚默认为输入，如果不把引脚配置成输出，写Output Port register不会影响引脚的值，但我一上电没有配置引脚为输出，直接写Output Port register，在引脚上也得到了想要的各种电平。这是怎么回事？
请解答，谢谢！
