Help to identify a chip

[nicky314]

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

 

[kpatz]

There are no numbers printed on the chip package?

 

[nicky314]

No numbers or reference at all. It has been erased.

 

[blueroomelectronics]

If it is a microcontroller and the part numbers sanded off you can bet the IC is copy protected.

 

[ronsimpson]

What circuit? What does it do (did)?

 

[nicky314]

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]

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

 

[blueroomelectronics]

Pick a microcontroller you're familiar with and make a carrier PCB.

It might be a simple DTMf IC.

 

[Nigel Goodwin]

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]

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 ) ?

 

[blueroomelectronics]

Sure it could even be a custom chip. What's it out of?

 

[Nigel Goodwin]

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]

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]

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]

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]

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]

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.