82-000760-01 Datasheet, PDF (28/44 Pages) Analog Devices – HPUSB USB and HPPCI Emulators

HPPCI JTAG I/O Voltage Detection
Figure 1-6. Legacy Switch Setting for HPPCI-ICE Pod
Auto Detection Mode
Auto detection mode is recommended for all newly designed target
boards. This mode supports 1.8V, 2.5V, 3.3V, and 5V target boards.
PCI-based emulators are 1.8V, 2.5V, and 3.3V-compliant in auto
detection mode. This means that the emulator can accept 1.8V, 2.5V, and
3.3V signals and can also drive the respective 1.8V, 2.5V, and 3.3V
CMOS level signals. The emulator is also 5V tolerant. Consequently, the
emulator accepts 5V signals and drives 3.3V signals to the target.
In auto detection mode, the emulator samples the target VDDIO signal
(pin 5 on the JTAG header) and drives the JTAG signals from the emula-
tor at the sampled voltage. The respective 1.8V, 2.5V, or 3.3/5V LED also
lights up to indicate the voltage at which the JTAG signals are driven.
The emulator is set to legacy mode before leaving the factory. The switch
must be set in the manner shown in Figure 1-7 to verify that the emulator
1-14
HPUSB, USB, and HPPCI Emulators User’s Guide