Notice that the TxD_data input needs to stay stable while the character is being sent. Keep that in mind when you use this module. You could also modify this module to register internally TxD_data when transmission starts.-Notice that the　TxD_data　input needs to stay stable while the character is being sent. Keep that in mind when you use this module. You could also modify this module to register internally　TxD_data　when transmission starts.