User`s manual

175
7.2 User System Interface
All user system interface signals are directly connected to the MCU in the emulator with no buffering except for
those listed below which are connected to the MCU through control circuits:
• NMI
• RESET
• MD2, MD1, MD0
• XTAL
• EXTAL
• WAIT
7.2.1 Signal Protection
All user system interface signals are protected from over- or under-voltage by use of diode arrays except for the
AVcc and Vref.
Pull-up resistors are connected to the port signals except for the analog port signals.
The PVcc signals (except for AVcc signals) at the head of the user system interface cable are connected together,
which is monitored by the emulator to detect whether the user system hardware is connected.
7.2.2 User System Interface Circuits
The interface circuit between the MCU in the emulator and the user system has a signal delay of about 8 ns due
to the user system interface cable and it includes pull-up resistors. Therefore, high-impedance signals will be
pulled up to the high level. When connecting the emulator to a user system, adjust the user system hardware to
compensate for propagation delays.
The following diagrams show the equivalent circuit examples of the interface signals.
Default:
47 k
User system
interface cable
MCU
47
PVcc
Ω
Ω
Figure 7.1 Default User System Interface Circuit
Mode Pins (MD2, MD1, and MD0): The mode pins are only monitored. The CPU mode depends on the High-
performance Embedded Workshop settings.
47 k
User system
interface cable
Emulator
control
circuit
47
PVcc
Ω
Ω
Figure 7.2 User System Interface Circuit for Mode Pins