Appendix B Differences Between The Actual Mcu And Emulator - Renesas R0E00030AKCT00 User Manual

E30A Emulator User's Manual

Appendix B Differences between the Actual MCU and Emulator

Differences between the actual MCU and emulator are shown below. When debugging the MCU using this product, be careful
about the following precautions.
Notes on Clock Setting:
The emulator sets the PLL-related settings before starting up in order to secure a communication path.
In a user program, be sure to set the same value of the PLL-related settings specified by the emulator
debugger. Otherwise, the emulator will be out of control. The divide ratios of the CPU clock and
peripheral clock can be changed in the user program.
The X clock is used to enter the debug mode and to stop the user program forcibly. Therefore, do not
IN
stop the X clock in the user program.
IN
The PLL clock divided by the base clock divider is used for communication between the emulator and
the MCU. Therefore, do not change the PLL frequency and the divide ratio of the base clock in the user
program.
When the emulator is connected, the PLL clock stop bits are ignored. Therefore, the PLL keeps
oscillating even when the WAIT or STOP instruction is executed. This means that BCLK is also
oscillating, so that control returns from WAIT or STOP by an INT8, 7 or 6 or other interrupt request.
The clock can be switched to a low speed clock (f256, fC, fOCO4). However, as the CPU operation
clock becomes slower, the response speed of the emulator debugger becomes also slower.
Furthermore, the internal flash ROM cannot be rewritten during a low speed clock operation. Therefore,
do not use software breaks.
Notes on Interrupt Stack:
The E30A Emulator uses an interrupt stack of up to 52 bytes. Make sure sufficient space is reserved for
the interrupt stack area, with the maximum stack size used by a user program added. If the reserved
interrupt stack area is exceeded, the user program may go wild or the emulator may be out of control.
The E30A Emulator sets the interrupt stack pointer (ISP) at the beginning address of RAM + 0100h
after being reset, and uses that location as a stack area at deassertion of reset.
Note on Interrupts That Cannot be Used by the User Program:
The BRK2 interrupt, single-step interrupt, and DBC interrupt are used by the emulator program.
Therefore, make sure the user program does not use these interrupts.
Note on Interrupt Request:
Even if a user program is not being executed (including when run-time debugging is being performed),
the peripheral I/O such as a timer keeps running. The interrupt request cannot be accepted, because
the emulator disables interrupts. The interrupt request is accepted immediately after the user program
execution is started.
Note on Low Voltage Detection Interrupt:
With this product, as the power voltage cannot be changed after powering on the user system, the low
voltage detection interrupt cannot be used.
Notes on Using the Watchdog Timer:
A user program can be debugged by using the MCU's internal watchdog timer if so desired. When the
watchdog timer is active, the debug monitor program refreshes it as necessary.
Watchdog timers connected external to the MCU cannot be used. Make sure those watchdog timers are
disabled while the emulator is in use.
R20UT0422EJ0501 Rev.5.01
Mar 15, 2016
Appendix B Differences between the Actual MCU and Emulator
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