How H P laser printer toner cartridge chip work?

hp toner chip protocol

Does anyone known, How H P laser printer toner catridge chip work?

such as HPLJ2300

see
Cartridge -> **broken link removed**
Printdetect Chip -> **broken link removed**

They are 2 wire memory chip or micro processor controlled?
and What protocol they are using?

RGDS,
ZeRoN
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toner chip microcontroller

I am also interested in understanding the protocol.

The chip is a PIC 12F683 microcontroller.

Communication is through 2 complimentary wires and the protocol seems to be
strange.

On scoping there are only bursts of fixed frequency
waveform. Not bit pattern, no stop bits, just a burst of monotonous square wave
with T=9.6uS.
The waveform is very neat and very periodic and it strange how communication is happening
through it.

The add to the mystery I tried counting the bursts. There is a variation of 10%.
Some burst count 1000, others as high as 100,000,000!
There is no indication that the toner stops the burst.

I concluded that communication is not through voltage, but through current.
How can I test if communication is indeed through current?

All I have is a two channel digital storage oscilloscope.

Any help is appreciated.
Sibi

hp toner cartridge chip how to work

Hi,
I was able to data log the communication from the toner chip to printer.

During power on the chip sends about 155x5bytes.
Most of them are similar except for only five 5 byte streams.

For example during 9 consequetive power on one five byte stream changes this way.
CB 51 06 6F 76
CB 51 40 07 C0
CB 50 44 27 F8
CB 51 40 2E 3A
CB 50 46 0E F8
CB 50 42 26 F6
CB 51 46 27 90
CB 50 40 4E 84
CB 51 44 4F E2


The change is vague. Could it be encrypted.
Any advice on what could be hidden?
Regards,
Sibi

Re: hp toner cartridge chip how to work

sibi said:

Hi,
I was able to data log the communication from the toner chip to printer.

During power on the chip sends about 155x5bytes.
Most of them are similar except for only five 5 byte streams.

For example during 9 consequetive power on one five byte stream changes this way.
CB 51 06 6F 76
CB 51 40 07 C0
CB 50 44 27 F8
CB 51 40 2E 3A
CB 50 46 0E F8
CB 50 42 26 F6
CB 51 46 27 90
CB 50 40 4E 84
CB 51 44 4F E2


The change is vague. Could it be encrypted.
Any advice on what could be hidden?
Regards,
Sibi

Click to expand...

How did you record the data ? i2c manchester code ? SSP ?
regards ficho

Re: hp toner cartridge chip how to work

ficho said:

How did you record the data ? i2c manchester code ? SSP ?
regards ficho

Click to expand...

ficho: you need a logic analyzer.

Like the Salae USB Logic Analyzer.
https://www.sparkfun.com/products/8938