“Intel 8080 Emulator on 4004 Evaluation Board
A self-made 4004 experimental board and an 8080 emulator running on it. We have achieved a level of functionality that allows Palo Alot Tiny BASIC to operate almost as it is.
- The P (parity) flag is not implemented by default. It can be changed with the assemble option, but the operation is unconfirmed.
- The DAA instruction is also not implemented.
- Interrupt-related instructions (DI, EI) are also not implemented.
- The IN instruction calls GETCHAR on the UART implemented in the software of the 4004 board, so it stops until it is input.
- The OUT instruction outputs the A register to the serial port of the 4004 board.
Experimental board specifications
- CPU: Intel 4004
- Clock: 740kHz
- DATA RAM: 4002-1 x 2 + 4002-2 x 2 (Total 320bit x 4)
- Program memory
- ROM: AT28C64B (8k x 8bit EEPROM)
- 3.75KB available from 000H to EFFH
- RAM: HM6268 (4k x 4bit SRAM) x 2
- 254 bytes x 16 banks of physical memory F00H to FFDH (The above is mapped to logical memory 000H to FDFH and accessed.)
- Communication Port: 9600bps Software Serial UART (TTL level)”