NEC V850/SF1 CHAPTER 4 CAUTIONS 4.1 VDD0 and PORTVDD of Target System

User’s Manual U15447EJ1V0UM
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CHAPTER 4 CAUTIONS
4.1 VDD0 and PORTVDD of Target System
(1) VDD0 in the target system is used to sense the level for target system power supply ON/OFF.
• When VDD0 is lower than 1 V, it is judged that the target system is not connected, and mapping of the target
memory cannot be performed with a debugger (FCAN cannot be used).
• When VDD0 is 1 V or higher, it is judged that the target system is connected, and mapping of the target
memory can be performed with a debugger (FCAN can be used).
(2) PORTVDD in the target system is not supplied directly to the emulator chip; it is connected to the target voltage
emulation circuit.
• When PORTVDD is lower than 3 V, VCC (5 V) in the internal emulator is supplied to the emulator chip.
• When PORTVDD is 3 V or higher, a voltage of the same potential as PORTVDD in the target system is
generated and supplied to the emulator chip.
Figure 4-1. Schematic Diagram of Power Supply Acquisition
Relay
V850/SF1
I/O chip
Target voltage
emulation
ON/OFF?
Evaluation
chip
Target
system
VCC (5 V)
PORTVDD
(66 pins)
VDD (8 pins)
IE-703079-MC-EM1 IE-703002-MC