![]() Our display has multiple lines (bit 3 = 1), and we set brightness to full (bits 1,0 = 0). We set the data interface length to 8bits (bit 4 = 1), but in serial mode this is probably ignored. Then, we start the transaction by taking the strobe pin low (a), and send the first byte with the R/W and register select (RS) settings. Before we start we set the strobe pin high in case it’s currently low. After a reset (power-up), the VFD expects the first command to be the function set a 0b11111000 0b00111000 įunction set configures the data interface length (bit 4), display lines (bit 3), and brightness/luminescence (bits 1,0). The Futaba VFD accepts all the standard HD44780 LCD commands (datasheet page 27), see these tables for a detailed description of each command. Read operations are similar to writes, except the R/W bit is set and the second byte is read. All transactions start with strobe low and end with strobe high. The LCD control bits (R/W, RS) go in the first byte, and eight data bits go in the second. The two-wire interface uses a straight-forward 16bit (2byte) protocol (datasheet page 20). ![]() CS is otherwise unused in raw2wire mode, so we reassigned the auxiliary commands to the CS pin (menu C,2). The auxiliary pin doesn’t have it’s own pull-up resistor but CS does. The VFD’s strobe pin is connected to the Bus Pirate CS pin. Finally, we enabled the on-board power supply (capital ‘W’). The open drain outputs let us interface the 5volt VFD from the 3.3volt Bus Pirate using the on-board pull-up resistors (menu P, 2). We setup the Bus Pirate for raw2wire mode (menu M, 7) with open drain outputs (HiZ). The connections we made between the VFD and the Bus Pirate are shown in the table above. We used our Bus Pirate universal serial interface to demonstrate the Futaba VFD, but the interface operations will be the same for any microcontroller implementation. Today we’ll demonstrate a serially-interfaced VFD using the Bus Pirate.įutuba VFD character LCD replacement ( NA204SD02, $7.00). The protocol type is set by resistors on the back of the display, so it’s not particularly easy to change without a hot-air rework station. ![]() ![]() VFDs have a wider viewing angle, and generally look cooler.įutaba’s character displays can be interfaced using the standard 8-bit or 4-bit parallel LCD interface, or a simple two-wire protocol. Futaba makes vacuum florescent character displays that can be used as a drop-in replacement for common character LCDs. ![]()
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March 2023
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