A simple panel with LEDs to show currently address and data, new address and new data, 2 sets of 16 LEDs to show the addresses and 2 sets of 8 LEDs to show the data, 16 switches to give new address and 8 switches to give new data.

A momentary switch to selects the new address, another momentary switch to writes currently data in the currently address, thats automatically increases by 1 the currently address, and a two positions momentary switch to increase or decrease the currently address.

Whenever the current address is changed, the current data is read automatically to be displayed on the panel.


In recent years, I have planned a homebrew computer. I gave the name Sofia (София) to the project because I'm using chips manufactured by the Bulgarian company Pravetz (Sofia is the name of federal capital city of the Bulgaria and the place of the one industrial plant of Pravetz company that manufactured these chips).

One of the project's goals is to avoid using or be dependent of external tools, especially modern ones, like emulators and cross-compilers.

To enter the first programs into memory, especially the firmware containing a machine code monitor and the simple device driver for serial communication, a panel like to the one used in the Altair 8800 is required, but without any software to control it.

This project aims to obtain that panel, controlled only by discrete integrated circuits (no CPUs, MPUs, PALs, GALs, CPLDs, neither FPGAs), that allows to write and read bytes directly into and from RAM and Flash EEPROM, through DMA, concurrent with the computer's processor.