Tektronix 492 USB Interface

I have a Tektronix 492 without GPIB. This project adds USB connectivity to the Tek 492. It can download a full sweep in about 200ms. It can't read any configuration from the instrument, so it's not a real replacement for GPIB, but it would be possible to emulate the control code and duplicate the front panel controls on the computer.

USB-492 PCB. The USB connector is on the other side.

This is a simple board with an AT90USB82 microcontroller. It plugs into the accessory port on the 492 and gives the host direct control over the instrument bus.


Spectrum of a TV station graphed in Octave.

Design Files

Use these at your own risk. As you can see in the photo above, the crystal footprint is wrong and I hacked a larger crystal onto the board.

I suggest you read the sections in the Tek 492 service manual that describe the instrument bus and microcomputer debugging. Timing diagrams and all register bits are described in the manual.

Schematics, layout, firmware, and host software