I’ve got some NOS 2×20 VFD modules. These modules are marked as “KD Rev 2.1″ or “KD Rev 6.0″ on the PCB. The “KD” presumably means “Kunden Display” (Consumer Display) and therefore where most likely used in a POS terminal. The modules only need a 5V supply and drawing up to 0.8 A.
The interface is a serial RS232 input using TTL level signals. When connecting the module to a computer use a level shifter (like the MAX232/MAX202) or any cheap USB-to-TTL converter. The last one can be obtained on ebay as Nokia DKU-5 or CA-42 data cables (see here for details).
The big connector on the left side is the ISP10 connector used for programming the Atmel microcontroller. This port should be left unconnected (unless you have the circuit diagramm and a new firmware). But lets take a look at the connectors and jumpers of the display:
|ISP||Atmel ISP10 programming connector|
|JP1||Jumper for Dot-Test-Mode|
|JP2||Jumper for Font-Test-Mode|
|J1||Primary interface connector|
|J2||Secondary interface connector|
The jumper JP1 and JP2 should be set/removed when the power supply is off. Those jumpers enable / disable the dot-test-mode / font-test-mode. J1 and J2 are interface connectors (J2 connector is not available in the older 2.1 revision). You can connect the modules using either J1 or J2 whereas J2 offers an additional feature: on pin 4 you can select the baudrate of the display. The default rate is 9600 baud and by connecting Pin 4 to ground, the display is communicating using 19200 baud. The driver supports both communications speeds – use the configuration dialog to select the correct one.
|1||Vcc||+5 V supply|
|2||Vcc||+5 V supply|
|3||RxD||Serial In (TTL level)|
|4||J1: Gnd||On J1 Ground|
|J2: BaudSelect||On J2 Baudrate selection (open/high: 9600 bps; low: 19200 bps)|
The connector J1 is from the DUBOX series by FCI. A matching socket can be found using FCI part number 65240-006LF. The J2 connector is from the Picoflex PF-50 series by Molex. The mating plug can be found under the Molex part number 90327-0306.
As you can see, the LCDHype logo is a compound of custom characters. The display itself supports one user defined character only, but I used a trick to enable up to 50 characters. You have to use LCDHype v0.7.5.3 or higher to use up 50 characters, older versions support up to 20 characters only).
The driver package will be included in the LCDHype setup starting with one of the next releases. You can also download the package from my site: