R0R521000EPB00 User’s Manual
2. Setup
REJ10J0844-0400 Rev.4.00 October 16, 2007
Page 39 of 88
2.10.2 Setting the POWER Selection Jumper
The POWER select jumper needs to be set depending on the user system’s power supply voltage and power supply condition.
If the system is used with power supply voltages in the range 2.7 to 5.5 [V], leave the POWER select jumper as set to the INT
side, which is the default setting. If the system is used with power supply voltages less than 2.7 [V], change the POWER select
jumper’s setting to the EXT side. When the POWER selection jumper is set to the EXT POWER side, this product consumes
max. 500 mA of electrical current from the user system. Table 2.3 shows the POWER selection jumper switch settings.
Table 2.3 Setting jumper switches on the R0E521000EPBM0
Switch No.
Switch name
How to set
Description
(Factory-setting)
When using this system with power supply voltages in the range 2.7
to 5.5 V.
JP1
POWER
selection
jumper
Set the jumper to this position when the user system’s power supply
voltage is less than 2.7 [V] and the user system’s power supply is to
be turned on/off.
When the POWER selection jumper is changed to the EXT side, following operations can be performed from the debugger
while the user system’s power supply is turned off:
(1) Starting up the debugger while the user system’s power supply is turned off, as well as downloading a program and
referencing or altering memory contents
(2) Starting program execution (by causing the program to run from an idle state, with the MCU in a reset state) while the user
system’s power supply is turned off, and then executing the program from a reset vector read phase when the user system is
powered up.
Furthermore, if the CPU clock is supplied by an on-chip oscillator, the following user system power on/off operations can also
be performed:
(3) Turning the user system’s power supply off during program execution and stopping the user program (by causing the
program to stop from the RUN state) while the power supply is turned off (the MCU in a reset state)
(4) Turning the user system’s power supply on or off while the user program is running or idle
Note, however, that since the reset pin is controlled from the emulator side, the high-going transitions of the VCC and
RESET pins for user system power-on occur with different timing, the power-on reset function of the MCU cannot be
debugged.
CAUTION
Notes on Setting the POWER Selection Jumper:
z
The user system’s power supply can be turned on/off only when the POWER selection jumper is set to the EXT
side. If an attempt is made to turn the user system’s power supply on or off while the jumper is set to the INT
side, the internal circuit of the emulator or the user system may break down. Therefore, such an operation is
strictly prohibited.
z
When the POWER selection jumper is switched to the EXT side, the upper limit of the external trigger input
level (VI) is 3.6 [V]. If the power voltage exceeding this limit, the internal circuit may be damaged.
IMPORTANT
Notes on the EXT Setting of the POWER Selection Jumper:
z
With this product, the MCU’s power-on reset function for user system power-on cannot be emulated.
z
The user system’s power supply can be turned on/off only when the system is operating with an on-chip
oscillator, and cannot be turned on or off when operating with XIN or XCIN.
INT
EXT
INT
EXT
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