因为这款单片机没有硬件串口，所以需要我们自己做软件模拟串口。

用PA3作为RX，因为PA3可以作为外部输入中断EXTI1。

本人首先用轮询的方式查PA3是否从高电平跳变到低电平（起始信号），但是因为还有别的业务逻辑，导致查询到低电平的时候，不能确定此时低电平过了多少us，导致后续数据采样时间点不正确， 实时性较差。

改用中断了以后问题解决。

GPIO初始化代码如下

void Ny8b072a_Gpio_Init(void)
{AWUCON = C_PA1_Wakeup;	// Enable PA1 input change wakeup functionIOSTA = C_PA0_Input | C_PA1_Input | C_PA2_Input | C_PA3_Input | C_PA6_Input | C_PA7_Input ; // set PA0/1/3/6/7 to input modeAPHCON = (unsigned char)~( C_PA0_PHB | C_PA1_PHB | C_PA2_PHB| C_PA3_PHB | C_PA6_PHB | C_PA7_PHB ); // Enable PA0/1/3/6/7 Pull-High Resistor,others disablePORTA = 0x20;	// PA5 output high//PA3INTEDG = C_INT1_En | C_INT1_FallingEdge;	// External interrupt 1 will be set while rising edge occurs on pin PA4INTE = C_INT_EXT1 | C_INT_PABKey;		// Enable External interrupt & PortB input change interruptBWUCON = C_PB5_Wakeup;	// Enable PB5 input change wakeup functionIOSTB =  C_PB5_Input | C_PB7_Input;		// Set PB5/7 to input mode,others set to output modeBPHCON = (unsigned char)~( C_PB5_PHB | C_PB7_PHB);PORTB = 0x0F;	// PB0/1/2/3 output highIOSTC = C_PC_Output;PORTC = 0x03;	// PC0/1 output highCPHCON = (unsigned char)~( C_PC0_PHB | C_PC1_PHB);
}

用了休眠功能，EXTI也可以唤醒。

 

中断里面接收代码如下

volatile unsigned int g_i = 0; 
unsigned char g_uart_rx_length = 0;
unsigned char g_uart_rx_buff[13] = {0};//! interrupt service routine
void isr(void) __interrupt(0)
{	if(INTFbits.INT1IF){ App_Delay_Us(26); //消抖52us//起始信号if(0 == REMOTE_RX_IO){//INTEDG = 0;	//PA4 is gpiowhile(1){for(g_i = 0; g_i < 8; g_i++){g_uart_rx_buff[g_uart_rx_length] >>= 1;App_Delay_Us(59); //104USif(1 == REMOTE_RX_IO){g_uart_rx_buff[g_uart_rx_length] |= 0x80;}}App_Delay_Us(59); //104US// 结束信号if(1 == REMOTE_RX_IO){if ( ('\n' == g_uart_rx_buff[g_uart_rx_length]) || (12 == g_uart_rx_length ) ){//INTEDG = C_INT1_En | C_INT1_FallingEdge;	// External interrupt 0 will be set while rising edge occurs on pin PA4//INTE = C_INT_EXT1;		// Enable External interrupt & PortB input change interruptINTF = (unsigned char)~(C_INT_EXT1);	// Clear INT0IF(External interrupt 0 flag bit)return;}else{g_uart_rx_length++;//wait for new startwhile (1 == REMOTE_RX_IO);App_Delay_Us(26); }}else{//INTEDG = C_INT1_En | C_INT1_FallingEdge;	// External interrupt 0 will be set while rising edge occurs on pin PA4//INTE = C_INT_EXT1;		// Enable External interrupt & PortB input change interruptINTF = (unsigned char)~(C_INT_EXT1);	// Clear INT0IF(External interrupt 0 flag bit)return;}}}else{INTF = (unsigned char)~(C_INT_EXT1);	// Clear INT0IF(External interrupt 0 flag bit)	return;}}
}//@16M  2T   2.5us
//App_Delay_Us(26); //52US
//App_Delay_Us(59); //104US
void App_Delay_Us(unsigned int count)
{	for(; count > 0; count--);
}

波特率9600 每一bit的时间是1/9600=104us，所以两个延时一个是52us一个是104us

延时函数是用示波器看过的，这里配置的是16M 2T

TX因为用不上所有没有去实现，不过思路是相同的，把IO口改为输出即可。