Timing Control Unit

The Timing Control Unit (TCU) is part of the 65c816. It contains a counter that is reset at each instruction fetch and advances during each machine cycle. Together with the instruction register, it helps the processor perform register transfers.

Reference

• section 2.2 of 65c816 datasheet: https://www.westerndesigncenter.com/wdc/documentation/w65c816s.pdf