
R0E417250MCU00 User
’s Manual
R20UT3587EJ0302 Rev.3.02
Page 220 of 232
Sep.01. 21
7.2 Differences between the Actual MCU and Emulator
Differences between the actual MCU and emulator are shown below. When debugging the MCU using the MCU unit, be
careful about the following precautions.
IMPORTANT
Note on Differences between the Actual MCU and Emulator:
⚫
Operations of the emulator system differ from those of actual MCUs as listed below.
(1) Initial values of registers
State
Register name
Emulator
MCU
Power-on/initialized
PC
Reset vector value
Reset vector value
ER0 to ER6
Undefined
Undefined
ER7 (SP)
H’10
Undefined
CCR
The I mask bit is 1
and the other bits are
undefined.
The I mask bit is 1
and the other bits are
undefined.
Reset
PC
Reset vector value
Reset vector value
ER0 to ER6
Undefined
Undefined
ER7 (SP)
H’10
Undefined
CCR
The I mask bit is 1
and the other bits are
undefined.
The I mask bit is 1
and the other bits are
undefined.
(2) Oscillator circuit
In the oscillator circuit where an oscillator is connected between pins XTAL and EXTAL, oscillation does
not occur because a converter board is used between the evaluation MCU and the user system.
(3) A/D converter
The characteristics of the A/D converter differ from those of the actual MCU because there are a converter
board and other devices between the evaluation MCU and the user system.
Note on RESET# Input:
⚫
A low input to pin RESET# from the user system is accepted only when a user program is being executed (only
while the RUN status LED on the E100 upper panel is lit).
Notes on Maskable Interrupts:
⚫
Even if a user program is not being executed (including when run-time debugging is being performed), the
evaluation MCU executes a debug control program. Therefore, timers and other components do not stop
running. If a maskable interrupt is requested when the user program is not being executed (including when run-
time debugging is being performed), the maskable interrupt request cannot be accepted, because the emulator
disables interrupts. The interrupt request is accepted immediately after the user program execution is started.
⚫
Take note that when the user program is not being executed (including when run-time debugging is being
performed), a peripheral I/O interrupt request is not accepted.
Note on Final Evaluation:
⚫
Be sure to evaluate your system with an evaluation MCU. Before starting mask production, evaluate your
system and make final confirmation with a CS (Commercial Sample) version MCU.