The NCR 7454 / Futaba M204SD01B VFD (vacuum fluorescent display) module is a large, bright, high quality display capable of displaying 4 rows of 20 character wide text. Each character is formed from a 5x7 dot matrix. These displays are made specifically for the NCR 7454 point of sale system, however new, surplus units are available inexpensively and are easily driven by the Arduino with as few as 8 pins. The Ncr4X20Vfd library was created specifically for this display.
The details on this page were arrived at by piecing together information from material linked to at the bottom of this page; examination and measurement of the display board; examination of an NCR 7454 point of sale system and experimentation.
|Supply Current Typical||800mA|
|Supply Current Max||1A|
|Communction Protocol||IEEE 1284 Parallel|
|Connector||Standard 30 Pin IDC|
|Pinout||Proprietary (See Below)|
The datasheet for the similar M204SD01AA display is linked to at the bottom of this page. Electrical and physical characteristics of the M204SD01AA may be the same or similar to this display. The M204SD01AA however has different electronics, connections, software interface, etc.
Caution: While the display operates on 5V, higher voltages are generated on board. As with all VFDs, the display board should not be operated outside of an appropriate enclosure.
In the above image of the rear of the board, pin 1 is located at the top right of the IDC connector.
|Display Pin||Arduino Pin|
Upon power-up the display performs a startup sequence consisting of all pixels being lit for approximately 2 seconds, followed by the part and version number (008-0221552 V1.02.00) displayed for two seconds. According to NCR documentation, a RAM self test is performed first and the display will halt operation of any problems are discovered.
During the power-up sequence the BUSY line is held high.
The communication protocol is IEEE 1284 parallel port as was commonly used by PC's to communicate with printers. According to NCR documentation the display supports ECP (Enhanced Capability Port) in addition to standard Centronics. Only Centronics mode has been tested.
The following sequence can be used to send a character to the display:
Characters are immediately displayed to the current cursor location.
The following are special control characters/character sequences.
* This is the power on default
International Character Set
Japanese Character Set
Code Page 850 Character Set