The EEM2TTL PCB board converts electrical signals between the LVDS interface and 3.3V TTL signals. It allows for selectable signal direction and optional 50-ohm termination. Power can be supplied either through the EEM interface or an external 12V power pin.
When the power source selection jumper is connected to the INT pin, the 12V power is supplied from the EEM interface. Conversely, if connected to the EXT pin, the 12V power is supplied from an external power source pin.
Each transceiver has four I/Os, and the direction of each I/O can be selected individually. Each I/O option is configured with a dedicated jumper, marked with an index number on the board. The upper jumper, labeled I and O, controls the transceiver's direction. When connected to I, it receives signals from TTL to EEM, and when set to O, it transmits signals from EEM to TTL. The lower jumper selects the FSEN option for M-LVDS, which stabilizes output even when the input LVDS signal is close to the threshold level and oscillating slightly.
A buffer chip is positioned directly behind the BNC port to increase output signal current. The direction of each signal can be selected by adjusting jumpers. Connecting the jumper to I routes the input signal from the BNC to the transceiver, while connecting it to O sends the signal from the transceiver to the BNC port. The OPEN and TERM jumper is used to control the BNC’s 50-ohm termination; connecting it to OPEN leaves the BNC open, while connecting it to TERM provides a 50-ohm termination on the board. This setup helps reduce signal reflection when receiving long-distance input signals.
The transceiver and buffer directions must be matched. Each direction can be selected individually on the board, mainly for debugging purposes, but this feature is typically not used. Connecting the jumper to DIR SHORT synchronizes the transceiver and buffer directions. When using this setting, never connect both the transceiver and buffer direction jumpers simultaneously, as this could short 3.3V and 0V. It is recommended to leave the I/O direction jumper on the buffer open and control the direction using only the transceiver direction jumper.
When jumper is connected to ON, board is turned on, and vice versa.