Oh my Ron
Now you are really making me feel old.
Seriously at the entire risk of boring the ass of anyone not so inclined to read further, i would like to explain.
I know Ron at least will appreciate this read.
In my long and now almost forgetten past, so past it seems like some previous life, i used to live and breathe Car radio electronics, just as i now do in the realm of vehicle diagnostics.
I would spend hours on end pouring over such manuals as this you have posted Ron, and sometimes i would even take them to bed.
I was single then though
Now i know better. Isn't age wonderful
It all started when i was an eager 18 year old. I was working as a junior in a Fiat dealership. As as i had a natural ability with all things electrical and electronic i found i was constantlty being asked to replace some quite nice OEM radios in both Fiats and other trade in makes with some after market rubbish.
Me being me, yea you know who i mean Ron, i constanly enquired as to why, i must have drove my employers nuts, and eventually i was told it was because they did not have the codes for these OEM ones. Inquiring further as to the extent of the problem, i was shown a cupbord in which they kept the removed radios. It was full to the brim with stuff i would have loved to own.
I offered to have a go at de coding these and was given an arm full of examples to experiment with. Well what did they have to loose.
As this was an age before internet and even the PC as we all know it today was only in its infancy, i had to order loads of books on memory devices, wait for them to arrive and i read them cover to cover.
Armed with this new knowledge i tackled a simple ford radio, no circuit diagrams were availible for Fords, but it had a distictly obvious 8 pin chip labeled MN010 showing a National semiconductors logo, which i suspected was really a National semiconductors MN9306 serial EEprom, which used a now common micro wire protocol.
Using an IO card designed for my trusty ZX spectrum, i connected the various pins and wrote a program to toggle the communication lines to ultimatley read the small amount of data it contained. The first register i read 00 contained 4 values something like 4217. And sure enough, by luck, when i entered a code of 421 into the radio, it burst into life. It seems that the 7 was the attempts counter.
The sucess inspired me to decode a phillips with another chip, I2C protocol (much more tricky) and much more common.
Sensing a whole new career, i quit my job with Fiat, started my first business, enlisted the help of a profesional PC programmer and created my first saleable software package which was leased to outlets across the UK on laptops with my own specifically designed hardware interface. We figured out just about all the manufacturers, Phillips, Ford, Sony, Blaupunkt, Pioneer, Kenwood, Audioline, Audiovox, Becker, Clarion etc. At that time Clarions codes were set by the simple solder joining (bridging) or not of a series of pad pairs.
The code base was always 1111 and the first pad pair would add 1000 or not, the second 2000 or not and so on. The maximum possible was only 6666 so there was only about 10 or 12 pairs.
I was so astute and tuned at the time that as a party trick i could pull the back off a clarion, look at which pad pairs were joined and within a few seconds calculate in my head it's security code.
These days i cant even remeber my wedding aniversary though.
But what i can recall and that may possibly be of use to others here is that on later Clarions like the P38 one is that they fitted a Microwire serial EEPROM which they labelled S2430, however the sneeky gits used a version on which all pins were rotated right by 2. IE on an industry standard 9346 or 9356, pin one is Chip enable but on an S2430, Chip enable is actually on pin 3 and so on.
So knowing this, it really is childs play to connect the S2430 epprom to any modern programmer and read its contents. Sadly i forget the exact registers that the code is in (I could look it up for the truly stumped though) but given that i figured it out over 20 years ago, it obviously ain't exactly gonna be rocket science.
I note in your manual Ron that the identity of IC117 is deleted, althogh the diagram shows that the enable, data in and data out pins of this mystery (yea really) 8 pin device give it away as my old mate the S2430, so as i said, This post of your manual does take me back, much more than anyone else might have been and i truly do thank your for the trip chap.
How do all you P38 owners generally get on with all the code malarchy these days anyway, i have been so out of touch since i have been into diagnostics.
If there is still a need to decode these P38 Clarions i could probably knock up a windows program to do it with a simple enough electrical interface to something like a printer port etc?
Nowadays i note that most car audio equipment has a security code which is derived from an algorythm of its serial number, and that manufacturers have much better traceabilty in place, so you can probably get security codes for radios etc via simple VIN number and proof of ownership, but it certainly was not always that way and i can but only hope that you enjoyed reading my own personal trip down memory lane. And whatever you do, don't put any radio in a freezer !!!
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