Note On Accessing Addresses 00000H And 00001H; Note On Stop And Wait Modes; Note On Display Of Mcu Status; Note On Breaks - Renesas M30290T-EPB User Manual

Note on Accessing Addresses 00000h and 00001h:

With the M16C/Tiny Series MCUs, when a maskable interrupt is generated, the interrupt data (interrupt
number and interrupt request level) stored in addresses 00000h and 00001h are read out. Also, the
interrupt request bit is cleared when address 00000h or 00001h is read out. Consequently, when the
address 00000h or 00001h readout instruction is executed or when address 00000h or 00001h is read out
in the cause of a program runaway, a malfunction occurs in that the interrupt is not executed despite the
interrupt request, because the request bit of the highest priority interrupt factor enabled is cleared.
For this malfunction, when the reading out to address 00000h or 00001h is generated excluding the
interrupt, the WARNING LED (yellow) lights up to alarm. When this LED lights, there is a possibility
of wrong access, therefore check the user program.

Note on Stop and Wait Modes:

Do not single step an instruction shifting to stop or wait mode. It may cause communication errors.

Note on Display of MCU Status:

"MCU status" you can refer to in the MCU tab of the MCU Setting dialog box of the emulator debugger
shows pin levels of the user system. Make sure that proper pin levels are specified according to the
mode you use.
(1) When single-chip mode is used:
CNVss: Low

Note on Breaks:

The area displaying break points in the program window of the emulator debugger shows the following
breaks.
(1) Address-match break "A"
This is a debugging function which breaks a program, using the address-match interrupt function of
the MCU, immediately before the system executes an instruction at a specified address. The
instruction at the preset address will not be executed.
(2) Software break "B"
This is a debugging function which generates a BRK interruption by changing an instruction at a
specified address to a BRK instruction (00h) to break a program immediately before the system
executes an instruction at a specified address. The instruction at the preset address will not be
executed.
(3) Hardware break "H"
This is a debugging function which breaks a program by setting the detection of an execution of an
instruction at a specified address as a break event. The program will break after the instruction at
the specified address is executed.

Notes on Address-Match Breaks:

As the processing speed of setting and canceling address-match breaks is relatively fast, you can save
the times of writing into the internal flash ROM of an MCU. Therefore, address-match breaks precede
the other breaks when setting breakpoints in the internal flash ROM area of an MCU.
Address-match breaks can be set only in RAM and ROM areas of an MCU.
Address-match breaks can be set at up to six points. The other breaks are set as software breaks.
Address-match breaks can be set or canceled even when the user program is being executed.
IMPORTANT
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Chapter 1. Precautions for Safety