• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Help to identify a chip

Status
Not open for further replies.

nicky314

New Member
I request your help in order to identify a microcontroller chip which is in a board I have to repair. I have been browsing a lot of datasheets from Microchip and Phillips and none fits:

Total number of pins: 14
Power VDD: pin 4
GND Vss: pin 11
pins 1,2,3, and 13 and 14: data input
pins 6, 9 and 10: data output
Pins 7, 8 and 12 are not connected on my board.

Most of datasheets I have seen from Microchip have Vdd on pin 1 and Gnd on pin 14 which is not the case on my circuit.

Any ideas will be welcomed.

Thanks
 

nicky314

New Member
It doesn´t matter if I can´t copy the contents.
What I am thinking is to prepare a new program myself.
I would prefer not to use a different microcontroller from the one on the circuit.
Regards.
 

nicky314

New Member
The circuit is a remote control. Only has a multitone dtmf decoder, the IC I think is the microcontroler and one output relay.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Assuming it's a micro-controller, it would certainly be copy protected, so there seems little point in erasing the number off of it. It's more likely to be a standard chip, which is why erasing it's number makes more sense.

If it's DTMF remote control, presumably it's really old?, as the crude DTMF system was only ever used for a short period, probably 25-30 years ago?.
 

nicky314

New Member
Nigel Goodwin wrote:" Assuming it's a micro-controller, it would certainly be copy protected, so there seems little point in erasing the number off of it. It's more likely to be a standard chip, which is why erasing it's number makes more sense."

Yes, your point is very interesting. But I don´t see how to do with a single chip - not being a microcontroller- the following:
A sequencial 4-digit ( 4 tones) password is received at the dtmf decoder which passes to the microcontroller different codes for each tone. if the password is correct then wait for a tone and depending on which tone, command a relay. If tone is #1 then set on relay #1, if tone is #2 then set on relay 2. Also if tone is #3 then set off relay #1 and so on...

Can this be achieved with a single chip (leaving dtmf tone decoding apart ) ?:confused::confused::confused:
 

Nigel Goodwin

Super Moderator
Most Helpful Member
It could well be a microcontroller, but there seems no reason to destroy it's markings if it is one.

So you have a DTMF decoder chip, and this outputs the value of the button pressed, presumably as a digital value on a four bit bus? - and passes that value to the next chip.

An extra concern for it not been a microcontoller is the absense of any clock components.
 

Sceadwian

Banned
Nigel, security through obfuscation, very effective. I do agree though that the chances of it being a micro controller aren't very high. With no markings there's nothing left to go on.
 

be80be

Well-Known Member
I never seen a micro controller sanded off. Number over but not sanded.
board I have to repair. I have been browsing a lot of datasheets from Microchip and Phillips and none fits:
If you have to repair and don't no what chip it is how do you no
So you have a DTMF decoder chip
whats it in
 

nicky314

New Member
So you have a DTMF decoder chip, and this outputs the value of the button pressed, presumably as a digital value on a four bit bus? - and passes that value to the next chip.
Exactly like you say.
An extra concern for it not been a microcontoller is the absense of any clock components
There is a xtal connected to dtmf decoder.

So, going back to my first post, anyone knows the reference of a 14 pin microcontroller with Vdd on pin 4 and gnd on pin 11 ?
 

Sceadwian

Banned
nicky, you're really shooting in the dark trying to guess like that, it probably wasn't a micro controller, it was likely a special purpose or custom IC. I like bluerooms idea of removing the old chip and connecting it to a daughter card mounted somewhere else in the case so you can re-route the VCC GND and data lines to whatever pins you want on the micro controller you chose. Determining the function the IC performed is going to be the hard part, as you may not be able to replicate it.
 

be80be

Well-Known Member
I have a parts book that list most all uC and I didn't fine one that matches what he is saying pin 4 VDD and 11 Gnd.
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top