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.
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.
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?.
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 ) ?
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.
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.
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.
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.