Update: SigmaLink USBi is now officially part of freeDSP project.

This is a clone of Analog Devices EVAL-ADUSB2EBZ USBi device for SigmaDSP devices - in fact it is a clone of a clone, based on the freeUSBi of freeDSP project but redesigned (yet again) from the ground up.

Difference from the official unit

Compared to the official unit, this clone brought forth a few improvements:

• It have a write protection jumper for the internal EEPROM device, preventing accidental corruption of the chip ruining the programmer.
• It is designed to fit inside a project case, instead of being used as a naked PCB. This is mostly a cosmetic difference, but an case does prevent some "whoopsie" moments like spilt coffee.
• It uses a cheaper microcontroller CY7C68013, hence the lower price.
• The target power supply is current limited to 500mA, also preventing some "whoopsie" moments when the target board is shorted.

However due to the cost-reducing and accident-prevention measure implemented, it also have the following limitations during use:

• The interface voltage is limited to 3.3V only. The CY7C68013 chip itself operates only at 3.3V, and the target interface lacked a target voltage sense line.
• The interface firmware cannot be updated without user intervention. When the interface attempts to update its firmware, the user need to disable the firmware write protection temporarily.

Story of creation

This device is part of my project building a DSP-backed headphone adapter.

The official EVAL-ADUSB2EBZ kits are sold at a significantly inflated price here, so I turned my attention to freeDSP and their freeUSBi kit. I wasn't exactly comfortable with the two-board construction of that kit, piggybacking on someone else's development board, and I happen to run across some nice project cases intended for small debug probes, so I redesigned the USBi yet again with those cases in mind.