这个很简单啊.你从main函数开始看, 看板子初始化的函数, 看UART初始化是哪个口, 不就是用的那个串口?!
#if defined(XPRJ_uart) // Defined by MPLAB X on command line when compiling "uart" Build Configuration
// Configure UART2 pins as UART.
// - Pin names are with respect to the PIC.
// - Outputs bits in TRIS registers are all set as inputs because the PPS or
// UART2 hardware overrides it.
//
// Function Explorer 16 PIM Header dsPIC33EP512MU810 Device Pins
// UART2 PIM#, PICtail#, name PIC#, name
// U2RX (in) 49, 34, RF4/PMPA9/U2RX 49, SDA2/PMA9/RP100/RF4
// U2TX (out) 50, 36, RF5/PMPA8/U2TX 50, SCL2/PMA8/RP101/RF5
_CNPUF4 = 1; // Turn on weak pull up on U2RX so no spurious data arrives if nobody connected
_U2RXR = 100; // U2RX on RP100/RF4
_RP101R = _RPOUT_U2TX; // U2TX on RP101/RF5
if(EZBL_COMBaud <= 0) // If auto-baud enabled, delay our UART initialization so MCP2221A POR timer and init
{ // is complete before we start listening. POR timer max spec is 140ms, so MCP2221A TX
NOW_Wait(140u*NOW_ms); // pin glitching could occur long after we have enabled our UART without this forced delay.
}
EZBL_COMBootIF = UART_Reset(2, FCY, EZBL_COMBaud, 1);
#endif