下列描述错误的是。
A. UART和RS232的电平是兼容的
B. RS232采用的是负逻辑
C. UART与UART互连，需交叉连接
D. PC机的COM口是RS232
下列初始化程序中，有错误的是。
A. NVIC_InitTypeDef NVIC_InitStructure； NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 7; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure);
B. NVIC_InitTypeDef NVIC_InitStructure； NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure);
C. NVIC_InitTypeDef NVIC_InitStructure； NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3); NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 6; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure);
D. NVIC_InitTypeDef NVIC_InitStructure； NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1); NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 7; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure);
微信支付 
支付宝支付