Designing Custom Processor Boards - Analog Devices HPUSB User Manual

Designing Custom Processor Boards

• VCC – This LED signifies that the board is receiving 5V power. If
this LED is not active, the HPPCI-ICE does not function properly.
• 3V – This LED signifies that the board is receiving 3.3V power. If
this LED is not active, the HPPCI-ICE does not function properly.
• FPGA[1:0] – These two LEDs are used for factory purposes only.
• DONE – This LED is activated when a VisualDSP++ debug ses-
sion is started. The LED should remain active even after the
respective session has been terminated. The LED shuts off and
re-activates at the beginning of every new VisualDSP++ session.
Designing Custom Processor Boards
When designing a custom processor board using Analog Devices
processors and DSPs, special care must be taken to ensure that the JTAG
interface is designed and laid out correctly. If the board is not designed
correctly, communication via the JTAG port may not work. Another side
effect may be that the interface works, but you are not able to run at the
highest possible JTAG clock frequency. The JTAG clock frequency is
dependant on the particular Analog Devices processor, as well as the delay
characteristics of the custom processor board.
To ensure that the custom board's JTAG interface is designed and laid out
correctly, refer to Engineer-to-Engineer Note, Analog Devices JTAG Emu-
lation Technical Reference (EE-68), available from the Analog Devices Web
site. This document is a technical reference for implementing the JTAG
interface on your target.
2-4 HPUSB, USB, and HPPCI Emulators User's Guide