We are using a TL15C552A to provide communications between two MCUs. Commands are sent from MCU1 to MCU2 and MCU1 responds through the SER0 port.
Operation is normal for some commands in that THRE goes high after the command is sent from MCU2 to MCU1 indicating that the transmit holding register is empty. But for some commands THRE never goes high even though the data is transmitted (we know this because MCU2 responds to the command).
What can prevent THRE from going high even though the data is transmitted?
