DEVICE TEST AND DEBUG USING POWER AND GROUND TERMINALS
The present disclosure describes a novel method and apparatus for using a device's power and ground terminals as a test and/or debug interface for the device. According to the present disclosure, messages are modulated over DC voltages applied to the power terminals of a device to input test/debug messages to the device and output test/debug messages from the device. The present disclosure advantageously allows a device to be tested and/or debugged without the device having any shared or dedicated test or debug interface terminals.
1 . An integrated circuit comprising:
A. functional terminals available to outside the integrated circuit;
B. power and ground terminals separate from the functional terminals;
C. functional circuitry having functional leads connected to all of the functional leads and power and ground leads connected to the power and ground terminals;
D. test circuitry, the test circuitry being connected to the functional circuitry and having test control leads for controlling the testing of the functional circuitry, the test control leads being free of the functional terminals;
E. test messaging and control circuitry having an input lead and having output leads connected to the test control leads;
F. demodulation circuitry having an input connected to a power terminal and an output connected to the input lead of the test messaging and control circuitry; and
G. filter circuitry connected between the input of the demodulation circuitry, the power lead of the functional circuitry, and a ground terminal.