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QB-78F1026
4.1.10 About countermeasure against floating of USB buffer
When enabled countermeasure against floating of USB buffer (IOR1EN = 0), the status of USBM pin differs between
the target device and the emulator.
Table 4-6. Operation of USBM Pin when enabled Countermeasure against Floating (IOR1EN = 0)
Target device
IECUBE
4.1.11 Performing emulation when using a USB connector
When performing emulation by using a USB connector, be sure to connect the VBUS check pin on IECUBE to VBUS
on the target system by using an IC clip. The IC clip used should be able to withstand the rated current supplied to the
target system. Also, make sure that the IC clip does not touch other components in the target system.
4.1.12 Performing emulation when using the USB connector on the target system
When performing emulation by using the USB connector on the target system, be aware that the differences in
electrical characteristics between the actual device and the emulated device are greater than when using the EMU USB
connector because the device is connected via an emulation probe or socket.
4.2
Debugging Note
4.2.1
Target system voltage during a break
Do not decrease the voltage of the target system during a break.
A reset that is generated by the low-voltage detector (LVI) or by power-on-clear (POC) during a break may cause an
incorrect operation of the debugger or communication errors.
4.2.2
Setting the USB operating clock value
Be sure to specify the correct value for the USB operating clock.
If the wrong value is set, the system will hang up when the SFR values are displayed by the debugger.
If the system hangs up, exit the debugger, and then specify the correct USB operating clock value.
R20UT0290JJ0100 Rev. 1.00
Sep 30, 2010
Item
Input
Fixed to low level (51 kΩ pull-down)
CHAPTER 4 CAUTIONS
USBM Pin
Page 29 of 29
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