Using the HP16500A Logic Analyzer with the 8031/8051 Microcontroller to Reverse Engineer its Code

The program “EXAMP05.ASM” was executed on the 8031 Microcontroller, and the logic analyzer was used to capture the instruction memory used inside the 8031’s rom. This simple program writes 0x00 in the internal static ram positions 0x30 through 0x7F. The HP16500A Logic Analyzer was used. The assembly listing was compared to the captured code. The logic analyzer was setup in state capture mode to trigger off of address 0x0800 where the beginning of the “EXAMP05.ASM” program resides.