PRC domestic CPU DG0040 discrete logic replication reverse engineering machine code compatible with the original version

The DG0040 series microprocessor system is a 4-bit high-performance microcomputer system jointly developed by Beijing 878 Factory (DongGuang Electrical Factory) and other units in the late 1970s and early 1980s. Its overall structure can be traced back to the Sharpe S-2/4 microprocessor in Japan. DG0040 is widely used in industries, agriculture, control, computing, and other fields. In the late 1980s, it withdrew from the market due to performance, cost, and other reasons.

This machine is powered by a single 5V and adopts a 6-micron silicon gate N-channel E/D MOS process. It integrates 11000 transistors on a single chip, with a 4-bit data width and a total of 48 instructions. Among them, 5 are double byte instructions, and some instructions are composed of up to 7 microcodes. When many instructions are combined, there is a special effect, with a maximum of 3 combined instructions. This also creates a super complex control circuit for the machine, and the programming is particularly unique. The CPU only has one general-purpose register, ACC, and 256x4bit SRAM, which greatly increases the manufacturing difficulty of the CPU. According to records, the yield rate is less than 25%.

Some people believe that the DG0040 is the PRC version of intel 4004, boviously, it's wrong, but not that wrong. The DG0046 interface chip is somekind a upgrade version of intel 4265, which is the P/SIO chip designed for INTEL-4004 and 4040.

Basic parameters: Production time: 1983-1985 Packaging: DIP-40 ROM addressing range: 8064 bytes. RAM: 256 * 4 bit. Input port: 4 bit Bidirectional synchronization port: 4 bits Output port: 4 (8)+16bit Main frequency: 100KHz

The replica integrates DG0040 and DG0041 on a single circuit board (15 * 25cm), using 74LS/74HCT series, Sigma N8200 series, Shangyuan Wu5G series chips, ATF16V8, and XC9572. The actual main frequency is 153.6KHz, and the theoretical limit main frequency exceeds 5MHz.

In terms of design, it is fully compatible with the original instruction machine code, but does not support compatibility with DG0046.