Cautions On Debugging - NEC QB-MINI2 User Manual

CHAPTER 5

5.2.7 Cautions on debugging

This section describes cautions on performing on-chip debugging for a 78K0S microcontroller.
Be sure to read the following to use MINICUBE2 properly.
(1) Handling of device that was used for debugging
Do not mount a device that was used for debugging on a mass-produced product, because the flash memory
was rewritten during debugging and the number of rewrites of the flash memory cannot be guaranteed.
(2) Cases where debugger operation speed is degraded
The debugger operation speed may be degraded when too many contents of the memory or registers are
displayed in a debugger window, particularly when using a host machine with a USB 1.1 interface.
The debugger response is also slowed while the flash memory is being overwritten.
This phenomenon may be improved to some extent by raising the CPU operation clock frequency, by setting
the PCC or PPCC register.
(3) Reset processing
If the RESET pin of the target device alternately functions as a port, enable the RESET pin by the user
program settings, such as option byte setting.
(4) When breaks cannot be executed
Forced breaks cannot be executed if one of the following conditions is satisfied.
• Interrupts are disabled (DI)
• Interrupts issued for the INTP pin, which is used for communication between MINICUBE2 and the target
device, are masked
• The alternate-function port corresponding to the INTP pin is not set to the input mode
• The external interrupt edge corresponding to the INTP pin is not set to the rising edge
• Standby mode is entered while standby release by a maskable interrupt is prohibited
(5) Flash self programming
If a space where the debug monitor program is allocated is rewritten by flash self programming, the debugger
can no longer operate normally.
(6) Operation after reset
After an external pin reset or internal reset, the monitor program performs debug initialization processing.
Consequently, the time from reset occurrence until user program execution differs from that in the actual
device operation.
HOW TO USE MINICUBE2 WITH 78K0S MICROCONTROLLER
User's Manual U18371EJ1V0UM
121