Renesas M16C/6N Network Card User Manual


 
M306NKT-EPB User’s Manual 4. Hardware Specifications
REJ10J0519-0200 Rev.2.00 Oct. 16, 2006 Page 95 of 104
IMPORTANT
Notes on Debugging in CPU Rewrite Mode:
z When you debug an M16C/6N Group M16C/6N4, M16C/6N5, M16C/6NK, M16C/6NL, M16C/6NM,
M16C/6NN MCUs in CPU rewrite mode, do not change the block 0 area (FF000h--FFFFFh) of the flash
memory. Otherwise, the emulator will be uncontrollable.
z If you check "Debug the program using CPU Rewrite Mode" in the MCU tab of the Init dialog box of the
emulator debugger, you cannot use the following functions.
(1) Setting software breakpoints in an internal ROM area
(2) Executing COME in an internal ROM area
z In CPU rewrite mode, do not stop the program. And do not single step an instruction shifting to CPU rewrite
mode. The emulator will be uncontrollable in CPU rewrite mode.
z To reference data after executing CPU rewrite, stop the program at other then a rewrite control program area
and use the memory window etc.
As the following interrupt vectors are used by the emulator system, the read data is different from expected
value.
(1) BRK instruction (FFFE4h--FFFE7h)
(2) Address match (FFFE8h--FFFEBh)
(3) Single-step (FFFECh--FFFEFh)
(4) DBC (FFFF4h--FFFF7h)
Notes on Address-Match Interrupts:
z When you use the address-match interrupt function in a user program, uncheck "Enable the Address Match
Interrupt Break Function" in the MCU tab of the Init dialog box of the emulator debugger. Thus, normal
software breaks are used for the internal RAM and ROM areas of an MCU.
z Do not set a software break at an address where an address-match interrupt occurs. Otherwise, a user program
may be run out of control. Set a software or hardware break in the top address in address-match interrupt
processing.
z When you single step an address where an address-match interrupt occurs, the program stops after executing the
first instruction after returning from address-match interrupt processing.
Note on Accessing Addresses 00000h and 00001h:
z With the M16C/60 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) on the upper panel of the PC7501 lights up to alarm. When this LED lights, there
is a possibility of wrong access, therefore check the user program.