E1 Datasheet, PDF (32/50 Pages) Renesas Technology Corp – E1/E20 Emulator

E1/E20 Emulator
Designing the User System
2.5.7. About the USER BOOT Pin
It is optional to connect a pin for entry to the user boot mode (UB pin) to the connector. Which port is the UB pin
depends on the MCU. Refer to the section on operation modes in the hardware manual of the MCU to be used.
Connection is not necessary if the MCU does not support the user boot mode.
When the UB pins of the E1 or E20 emulator and the MCU are connected to each other, you can perform
debugging without worrying about switching the UB pin between high and low on the user system because it is
done by the E1 or E20 emulator. Note that if the MCU supports a USB boot, the UB pin cannot be used as a port
because it must be controlled by the emulator. If the MCU does not support a USB boot, the UB pin can be used as
a port, instead of being connected to the emulator, as far as a user boot is not used. In this case, set the UB code so
that a user boot is disabled.
[When the E1 or E20 emulator controls the UB pin]
You can debug a program in user boot mode.
Pull up or pull down the UB signal at 4.7 kΩ to 10 kΩ according to the operation mode of the MCU used.
When programming the on-chip flash memory by using the programming software, set the programming software
so a low-level signal will be output from the UB pin.
[When the E1 or E20 emulator does not control the UB pin]
You cannot debug a program in user boot mode
Pull up or pull down the UB signal at 4.7 kΩ to 10 kΩ according to the operation mode of the MCU used.
When programming the on-chip flash memory by using the programming software, pull down the UB signal using
a switch.
[When the E1 or E20 emulator controls the UB pin]
Connector
Pull up or pull down at 4.7kΩ to 10 kΩ*¹
UB
UB
Note: 1. Pull up or pull down the pins according to the operation
mode of the MCU used.
MCU
[When the E1 or E20 emulator does not control the UB pin]
VCC
Connector
4.7kΩ to
10 kΩ
4.7kΩ to
10 kΩ
MCU
UB
UB
If the internal memory is to be programmed, use switches on the user system to
set the levels on the UB pin to select boot mode. Otherwise, set the levels on the
pins to place the MCU in the required operating mode.
Figure 2.21 Connection of the USER BOOT Pin
Do not install capacitors, series resistors, or filters on signal lines; if attempted, correct communication may not
be established.
R20UT0399EJ0700 Rev.7.00
Feb 01, 2014
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