The microcode sequencer is loaded with the next instruction from the computer program and then steps through the microcode program associated with that instruction. A micro-code program is a very simple program that consists of a small number of micro-instructions and each micro-instruction enables one or more control signals that drive the other components of the CPU.
Data bus - The connection to the 8 bit data bus enables the next program instruction to be fetched from memory and loaded into the microcode sequencer.
Zero flag - The zero flag from the Control Register is used to implement conditional branches. The microcode sequencer checks the value of the zero flag to determine whether to implement the conditional.
Interrupt - If enabled the micro-code processor will run a microcode program to service the interrupt rather than load the next program instruction.
Interrupt # [0-n] - The identifier of the device that has raised the interrupt is is placed on the interrupt #lines.
Control Signals [0-n] - The control signals are enabled according to the micro-instruction.
Reset - Enables the microcode sequencer to be reset to a known state on power on or reset.
Clk - The clock provides the timing signal to step through the microcode program.
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