Fast embedded A/D converter testing using the microcontroller´s resources

It is shown that embedded analog-to-digital (A/D) converters in microcontrollers can be tested more thoroughly and more quickly on digital VLSI test systems by using the microcontroller, rather than the tester, to tally all A/D conversion codes. These tally data are then transferred to the test program in one sequential stream, thereby reducing the test time required to evaluate the A/D transfer characteristics. For the 8-b microcontroller used in the present work, the histogram method was chosen over the servo method because the histogram method was faster and required almost no device load board hardware to implement. The present approach will save significant test time over previous methods of implementing a histogram A/D test on digital VLSI test systems. An added benefit is that the microcontroller under test is exercised while performing the A/D conversions. Hence, the transfer characteristic measurements also take into account normal device operating noise