emdarcher/vintage_beauty

Driving vintage HP HDSP-2000 Alphanumeric LED displays with a retro EPROM 8051 Microcontroller.

Vintage Beauty

Driving vintage HP HDSP-2000 Alphanumeric LED displays with a retro EPROM 8051 Microcontroller.

I made this project because I love Vintage Hardware and wanted to make something cool with the LED displays and an old 8051 that I had. End goal is to implement Character LCD emulation on the GPIO so it can act as a drop in HD44780/HD66702 based Character LCD replacement.

I also wanted to take on the challenge of optimizing the code to run fast enough with the limited speed and peripherals of the 8051 Microcontroller. As a result, I got to learn the 8051's memory map with more detail in order take advantage of the bit-addressable RAM on the chip for a fast bit-banged SPI output, which was pretty fun.

Pulished on Hackaday Projects as an entry into the Beautiful Hardware Contest here.

Demo:

Check out the Vintage Beauty Demo program in the demo folder

Features:

• Can display the US ASCII character set, as well as Japanese Katakana and Hiragana using a custom 5x7 pixel font stored in the program ROM. (I love Japanese, so had to get it in there!)
• The ROM character sets are based off the those in the HD66702 LCD driver chip found in many Character LCDs.
• Communicates with the displays through an optimized Bit-Banged SPI-like protocol utilizing the the 8051's bit-addressable memory for speed. Based on code found here but modified for SDCC.
• Written in C and compiled using the Open Source Small Device C Compiler (sdcc)

Work in Progress:

• Full HD44780/HD66702 LCD Driver emulation via GPIO ports.
• Serial UART control.

References and Datasheets:

• HD66702 LCD Driver Datasheet (For ROM Reference)
• HDSP-2000 Datasheet
• Intel 87C51 Datasheet