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I have a problem with a sbc that I am repairing, the sbc is controlled by an 8-bit OTP microcontroller which I think is broken. I only get 200 ohms between pin Vcc and Vss, specifically the chip is COP87L84BC and is out of production.

What I try is to read the registers of the microcontroller with a cable ISP and any similar software WinPic800 but for this chip. I never used the COP8 OPT from National Semiconductor so I wanted information about this MCU or web sites where I can find information.

Chetan Bhargava
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jotasa
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    welcome to the dark side of rapidly evolving technology :/ – Jason S Nov 26 '09 at 05:50
  • jotasa, I know you are probably losing hope, but I should be able to read all of their documents this thursday evening and get you an answer. – Kortuk Nov 29 '09 at 18:42
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    I am not going to make this an answer, as it is not one, I do not see more information about it easily, but the datasheet is all I need to reverse engineer it. You should be able to do everything this chip does with a 3 dollar PIC. If you could figure out what this chip is connected to(Pin numbers are important) I can help post an answer about how to approach a reverse engineering job. You really need a working one for a full reverse engineer, or see if the system engineers will give you more information since it is out of production. – Kortuk Dec 04 '09 at 01:15
  • I don´t think you can read any information at all from this chip, and even if you can, what´s for? You cannot buy it anymore. Spend your time writing code for a new MCU, forget about COP8! – Andre Oliveira Jul 08 '10 at 02:49

2 Answers2

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200 ohms between Vcc and Vss: are you sure the MCU is to blame? You would have to remove it completely from the circuit just in case there is something else connected to the Vcc rail that is actually faulty.

If you apply power, do you see any of the I/O lines changing state?

Adam Lawrence
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Not really sure what your question is but the data sheet is here

Theres a section covering development tools near the end.

Its a one time programmable unit so don't expect an in circuit programming connection of any sort nor debug support.

Its very doubtful you'd be able to read the program out of the chip at all, at least not without some very specialized hardware.

Mark
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