To clear the receive buffer for a selected peripheral port, send the control character followed by ASCII capital R. All complete or partial messages in the buffer of the selected peripheral port will be erased regardless of the mode of operation.
In Mode of Operation 1, the H-Series multiport will provide full duplex communication between the host port and the selected peripheral port. Port 2 is the selected peripheral port when the multiport powers up. The host port and the selected peripheral port will remain connected until another peripheral port is selected. Data received by non-selected peripheral devices will be stored in the multiport's buffer and sent to the host device when the peripheral port is selected.
When switching ports, there may be some question as to which is the last character received from the current port and which is the first character received from the new port. A way to avoid this confusion when selecting a new port is to wait two character times between Control-Tand the port number. When the multiport receives Control-T, it stops the input of data to the host UART from the current port. However, since the UART has some buffer, up to two characters may still be sent to the host device. The multiport does not start loading data from the new port into the host UART until the new port number is received. This delay may be accomplished by sending a string of ASCII zeros (30 Hex) between Control-Tand the new port number.