TM4C123GH6PM: Hi Bob Crosby,I don't know why I canot reply to your answer In problem that uart(1-7) cannot work, when I clicked your reply ,it always show blanks. ,so I can only ask a new question about that,really thanks.

Part Number: TM4C123GH6PM

now I know that uart0 is a virtual port ,so I can use it to communicate with my PC,other uart module cannot communicate with PC by serial port .I am learnning about how to communicate between

two or more MCU or DSP, (by UART SPI  CAN  I2c  or other ways),I am a student and fresh about these. could you give me some advice or Learning materials on this and how to test communicate correctly . Thank you very much for your help.