CHAPTER 3 CPU
Preliminary User’s Manual A14874EJ3V0UM
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3.6 RCU Interface
3.6.1 Outline
The RCU interface is a bus interface for connecting the NU85E to the NB85E901 (run control unit (RCU)).
The RCU communicates with an N-Wire type in-circuit emulator by using JTAG and executes debug processing.
Figure 3-12. Connection of NU85E and N-Wire Type In-Circuit Emulator via RCU
NU85E
JTAG
NB85E901
(RCU)
N-Wire type
in-circuit emulator
3.6.2 On-chip debugging
By connecting the RCU to the NU85E, on-chip debugging (an on-board debug function) can be realized. The CPU
of the NU85E is equipped with a breakpoint function, which can detect breakpoints based on the execution address,
access address, access data, range (address mask), or 2-stage sequential execution, as well as a break interrupt
function operable by external port input. Connection of the RCU to the NU85E allows not only debugging using these
functions, but also makes possible the employment of a background monitor JTAG system ROM emulator and an N-
Wire type in-circuit emulator.
