Oki's ARM MCUs have a built-in On-Chip Debug capability facilitated through the EmbeddedICE macrocell built-into each chip. EmbeddedICE is an extension to the core architecture and provides the ability to do in-circuit-emulation with deeply embedded cores.

The EmbeddedICE macrocell, adds a Joint Task Action Group (JTAG) TAP controller and breakpoint/watchpoint logic to the ARM microcontroller which can be accessed externally through a JTAG port. Hence, software debug is facilitated by interfacing these JTAG pins of the micro to the host development system containing the ARM software development tools through a JTAG interface board such as ARM MultiICE. The following figure illustrates the connection between a host development system and the JTAG port of Oki's ML674000 CPU board.

ICE = In Circuit Emulation