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What tools and techniques can I use to identify an unknown IC with no markings?

Today I encountered a microcontroller under an epoxy blob. The blob had 11 pads on each of four sides, perhaps 44tqfp. From the board, I know which pin is the reset line and I probably know which pins make up an SPI interface.

Is there such a thing as an expert system for answering these puzzles with the information I have?

Are there any searchable databases of pinouts online?

Would X-raying/Decapping the package be worthwhile?

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    \$\begingroup\$ Are there any obvious pads on the board for production programming? \$\endgroup\$ – Nick T Jan 14 '11 at 0:59
  • \$\begingroup\$ @Nick Yes, there are 6 marked pads, GND, RESET, SI, SO, SCLK and VPP - hence I know where reset and a SPI bus are \$\endgroup\$ – Toby Jaffey Jan 14 '11 at 1:01
  • \$\begingroup\$ More modern MCUs aren't programmed through the SPI though, but some proprietary interface (sometimes parallel for high-speed) \$\endgroup\$ – Nick T Jan 14 '11 at 1:04
  • \$\begingroup\$ Good point, it could just as easily be a SPI debug port, or test interface \$\endgroup\$ – Toby Jaffey Jan 14 '11 at 1:09
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    \$\begingroup\$ those 6 pads sound a lot like a PIC ICSP programming interface. You could try connecting a PIC programmer to read out the chip ID. \$\endgroup\$ – markrages Jan 14 '11 at 4:05
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X-ray won't tell you much. Dimensions of the chip and where the bonds are attached. Decap is probably necessary. You should be able to get the manufacturer from text on the die, which will be a big clue. If you are really lucky, the manufacturer will put something on the die to help you ID the part number.

If you have a subscription to a tear-down company, you could scan their die photos and if you are luck find a match.

For a fee, a tear-down company will do this work for you and send you a full report on the part. Here's a list of a few such companies:

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    \$\begingroup\$ Thanks, I didn't know there were companies who could do this for you. \$\endgroup\$ – Toby Jaffey Jan 14 '11 at 20:04

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