I have a commercial PMR radio, a UHF Pye MX296 which is single channel and needs bringing into the amateur band. My limited research tells me that it uses a 2716 Eprom for the channel data. In thinking about how to organise an Eprom blower, I just wondered whether I could press a microcontroller into service as an emulator perhaps?
AJLElectronics:
I have a commercial PMR radio, a UHF Pye MX296 which is single channel and needs bringing into the amateur band. My limited research tells me that it uses a 2716 Eprom for the channel data. In thinking about how to organise an Eprom blower, I just wondered whether I could press a microcontroller into service as an emulator perhaps?
I have not seen a 2716 Eprom since the early 1980's. Surely you can open the box and see the 2716, they are huge compared to today's components.
What in the world is an Eprom blower. I remember setting in a darkened office while programming them so I could detect a flash of light inside the window, meaning the programmer had popped one of the connecting leads to the die. Are you referring to a programmer? The 2716 requires a high voltage pulse to do the programming.
Paul
EPROM emulation is a matter of speed. Almost no problem if you can hold the processor until the Arduino can provide the requested data. Otherwise a very fast Arduino is required for servicing an EPROM Read in time.
From what I gather, it isn't a 2716 but an 82s129 which is a very fast bi-polar PROM. It would seem that is is very very fast, very rare and very expensive. Then it is a pig to program. Therefore I would think that the Arduino may not be a good choice. Why Pye used such a fast device, I can't really tell because it is only a frequency synthesiser. There is someone selling conversion boards on Etsy to the 27512 which is a fast EEPROM. that may be the route I have to take.
Paul, an Eprom blower is English for an Eprom programmer. (Slang term really, but I do love to have a pop at the mangled version of English you use over there)
Pye? :o
2716 is dog slow compared to todays parts
450nS access time.
You could wire in an FRAM for non-volatility
https://www.digikey.com/products/en/integrated-circuits-ics/memory/774?k=parallel+fram&k=&pkeyword=parallel+fram&sv=0&pv2043=383917&sf=0&FV=-8|774&quantity=&ColumnSort=0&page=1&stock=1&pageSize=25
Pick one of the 5V parts, program it with an Arduino, wire up a socket to socket converter, and be golden.
"Pye? :o"
Got a problem with that? Pye if you are unaware were one of the biggest manufacturer of PMR and domestic radio equipment from the late 50s onwards. You will find Pye branded equipment in everything from System 3 radio telephones, to Police communications. Marvellous equipment and the older stuff at least is generally easy to get into and do things with.
It appears that I have a mismatch between the manual I have, for an MX296 and the radio I have which is an M296. The latter appears from a look at its board not to be a synthesised radio, but I need to do some more research now. If it is rock bound, it will cost me more in crystals than is decent to spend. British readers will be familiar with my hero and role model, Arkwright who is Open All Hours.
from: Open All Hours - Wikipedia
Arkwright
Main article: Arkwright
Albert Arkwright is a pragmatic, miserly man with old-fashioned values, whose world seems to stop at his shop door, except for his uncontrollable lust for Nurse Gladys Emmanuel, which may prompt him on occasion to wander across the road, usually with a ladder, to gain access to her bedroom window. Arkwright is a devious and mildly dishonest character, who has many crafty tricks to try to persuade a customer to leave his shop having bought at least one thing, and will avoid spending his own money at all costs. He is also very protective of his savings, keeping some in his pocket wrapped in a fine gold chain, and some in an old, battered Oxo tin that he hides under the kitchen sink. This includes, or so he claims, coins from before 1922, when they were "solid silver".
"2716 is dog slow compared to todays parts"
Yes quite which is where my musing started. Then the goalposts moved when I read in the manual it is the 82s196, a completely different animal. I need to get my ducks in a row before I go any further down that road, now I realise that I have an older version that may not even be synthesised.
Thanks for your valuable input, it will give me more to think about.
The question so far ignored here is - what does the EPROM actually do?
If it stores the program for a microprocessor, then you have a problem.
If it takes inputs from a channel selector switch and gives a static output, you have no problem at all, just use a 74HC595 and a couple of 74HC165s to read the input and formulate an output.
Only once you know what it does, you can proceed.
Paul__B:
The question so far ignored here is - what does the EPROM actually do?
A good question Paul. As far as I can see from the circuit diagram, it only provides a reference to the synthesiser. I can't for the life of me work out why an 82s196 would be needed to do that job, unless Pye had got a good deal on a few thousand perhaps.
Paul__B:
If it takes inputs from a channel selector switch and gives a static output, you have no problem at all, just use a 74HC595 and a couple of 74HC165s to read the input and formulate an output.Only once you know what it does, you can proceed.
Quite right too. No point in just knowing that the answer is 42, if you don't know what the question is.
I am negotiating on buying a later MX296 and that quite clearly has been modded with a 2716 on a length of pretty ribbon cable and has a toggle switch to select the bank required; messy.
I will give more on that if my bid is successful. I see no reason why that couldn't be emulated by a microcontroller, so will give it some thought. Probably easier than re-inventing the wheel with a new synthesised VFO like I may have to do with the older M296 model.
28c16 eeproms seem to be still available at reasonable cost (and much easier to program than the 27c us-EPROMs.
I can’t find any sign of an 82s196 (82s129 seems to run about $10)
"HERE I HAVE A PYE-PHILLIPS MX296 70CMS FM MOBILE RADIO USEING A 2716 EPROM GIVES IN THEORY 48 CHANNELS, HOWEVER ONLY HALF HAVE BEEN PRE-PROGRAMMED, IF YOU ARE GOOD WITH HEX CODES AND CAN WIPE CLEAN THE REPROGRAM THE EPROM USING YOUR OWN CHANNELS.
AT THE MOMENT IT HAS REPEATER, REVERSE REPEATER AND SIMPLEX CHANNELS.
10 WATTS RF AND SQUELCH OPENS AT -117dBm"
Here is the 2716:
I did a little googling and found the service manual, from which it appears the eprom supplies the divisor to an NJ8813 programmable divider in the form of four 4-bit words of data. Closest data sheet I can find is for an NJ8811/NJ8812, if those are similar enough the timing is well in the microsecond range. The programmable divider chip supplies the lower two bits of the address for the eprom.
Looks promising for direct connection to an atmega chip, and the datasheet for the programmable divider chip gives the equations for calculating the divisor value.
CrossRoads:
You could wire in an FRAM for non-volatility
Thankyou, that is something else I have learned today.
david_2018:
I did a little googling and found the service manual,
So would you care to post the link?