I have designed the ADAU1702 into an engineering breadboard, using the MINIB eval board as the basis of the design. I've replicated the circuitry as exactly as possible, but cannot get communications working with SigmaStudio via the ADUSB2Z adaptor board... yet when I plug into a genuine ADI eval board, it works fine. I'm wondering about the use of pin 2 on J8 of the mini eval board... it appears to have the label 'USB_CLK', but there is no other signal with that name in the schematic.... yet the ADUSB2Z adaptor board appears to make a connection to this pin via the flat cable. Can you tell me what this signal is, and whether it is essential for communications?
The problem is solved, and indeed, it was related to the WP pin. However, it does demonstrate a major problem with the documentation for this part.
For one thing, the pin is described in the pin list…
Tie the selfboot pin low when you want to communicate with SigmaStudio. Once you have your project functional you can program the EEPORM then tie the pin high so it will boot from the EEPROM…
Ok, so you already did what I would ask next which is see if it is being held in reset. So the part is basically dead/not alive. So go back to the basics and make no assumptions. Check all…
It may not matter, but I did notice a difference in reset circuits for the two boards. The 1701MINIZ board processes the /RESET from the USBi through the ADM811 (into pin 3 and out pin 2):
Your prototype board directly parallels the ADM811 output (pin 2) with the USBi /RESET (header pin 6). Since both these signals are negative logic the difference appears inconsequential -- yet perhaps running the USBi /RESET through the ADM811 provides a cleaner reset to the -1701.