Device Files

A device file, as the name suggests, contains information about a single device and functions to test that device. Everything in a device file is circuit independent and consequently completely reusable across projects. Once a device file has been developed, it may be used without modification in the XJTAG test system for any circuit that contains the device.

Device files are required for non-JTAG test devices that are either:

• connected directly to devices on the JTAG chain under test, or
• connected via a connect device to devices on the JTAG chain under test.

Device files are NOT required for Ignored devices and connect devices.

The files are divided into two sections:

• Device Preamble - Contains a description of the device, in terms of assigning meaningful names to pins and busses, and a device disable function.
• Device Functions - This section is optional and may be omitted for connect devices. It contains functions to test the functionality of the device.