The Microchip Technology Inc. 27C64 is a CMOS 64K bit (electrically) Programmable Read Only Memory. The device is organized as 8K words. 27C64 64k (8k X 8) CMOS EPROM FEATURES. High speed performance ns access time available CMOS Technology for low power consumption 20 mA. 27C64 EPROM Datasheet, 27C64 64K EPROM Datasheet, buy 27C

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Remember the 27C64 has 13 address lines so the values on them can be from to 1FFF but the output is 8 bits so can only go from 00 to FF. If that isn’t physically possible to do, with the power off, measure the resistance between the GND pin and nearby chassis to make sure they really are connected then use the chassis as the negative connection point.

Programming File for 27C64 Eprom Sorry for the late reply – I’ve had a minor accident and can’t sit upright at the moment! I’m more or less upright again now so “on with the work!

27C64 EPROM Datasheet

Thanks again for your time, Regards, Chris S. Equating complex number interms of the other 6. Turn on power triac – proposed circuit analysis 0. Similar Threads Eprom programming help 8.

It that is the case, and if the radio is working at the moment, I suggest you note the voltages on the EPROM outputs for each channel number you select.

There will be gaps in the contents of the EPROM so don’t worry if there are empty addresses you don’t use. Each of the 4 bit patterns is translated to a single hexadecimal character like this: Dprom tuning, Part 2: I am not fluent with Eprom programming and i have probably messed up the conversion from Binary to hex or placed it in the wrong location.

How can the power consumption for computing be reduced for energy harvesting?

27C64 – 27C64 64K EPROM Datasheet

I have 10 channels but if you could possibly show me this one example i can work the rest out by trial and error, hopefully. It would be useful to note this because you may be able to use it to calculate new channel frequencies.

Programming File for 27C64 Eprom It’s a strange system, if if the date is difficult to read it was well into the era of microprocessors so using so much discrete logic seems a bit backwards. Dec 248: The trouble is it has a fluorescent display and few modern processors can drive it directly. You have cleared up a lot of my confusion over this and have given me a Good place to start, time to do some serious study.


Bits 7, 6, 5 and 4 make the first character and bits 3, 2, 1 and 0 make the second character.

It makes reading and writing a bit difficult. You can always tell a programmer by the way they count on their fingers then take their shoes off to count on their toes as well! I would be very grateful for any further assistance you might be able to provide on the above. I have attached a small portion of the instructions that were included in the manual regarding the odd way the data is entered to complete the Eprom. Programming File for 27C64 Eprom I’m back again – sorry for the delay, I’ve suffered from a spine problem for years, it causes unpredictable spasms that probably look quite comical to watch but having slipped and torn a muscle in my lower back the last thing I eprlm was any 227c64 movements!

Programming File for 27C64 Eprom Thanks Brian, I am still having trouble getting a Correct Eprom image that will work correctly combining the Channel change module and the radio Module.

Remember it doesn’t hold a program, it’s just a look-up table so it wouldn’t use more addresses than there were things to look up. When you have done it for all the input combinations you need, program the chip. Thanks again for your help, Tait Measure the voltages on all the Address lines and write down whether they are high or low as a binary number, for example: Would you have a minute to take a look at a file i have produced in regards this.

I have printed out your 27×64 and will study it tonight in detail when i can concentrate on it fully. I don’t mean to take up all of your time but i would be really interested in hearing more about the microprocessor option if you are able, there is plenty of space on the channel change module and might be easier to generate a small board that could plug in in place of the Eprom.


Would it be possible for you to take a quick look and tell me where, looking at the diagram i eeprom enter the data to have “01” selected on the Push Buttons and have “DO” pin 11 pulled low on the Eprom output? It is very easy to convert the bit pattern from binary to hexadecimal. Apologies for the long first post but if anyone could point me the right direction as to how to create this file i would be most grateful before i wear out my UV Eraser or the Spare Eproms i have been using to test the files Regards.

Programming File for 27C64 Eprom

Programming File for 27C64 Eprom Hello Brian, Hope you are feeling a bit better, Would you mind having a quick look at the attached Circuit diagram of the other end of this Combination and tell me if i can do a check of which Data output lines coming out of the Channel change module are either “High” or “Low” depending on which Channel is selected?

This means only of the possible EPROM addresses are actually used and although not marked on the schematic, address lines A8 upward are all unused and tied to ground. For example if the input lines were the address is C and you wanted to output on the data lines the value to place in C would be 9B. I don’t know if this is correct and would be very grateful if you could point out any mistakes in my file as it does not look like any.

You will see distinctly different voltages on the pins and they will almost certainly be very close to 0V or 5V.

There will be a “no mans land” zone at and possibly around the 2. After i asked you about using the DVM to e;rom whether the output lines were at the correct Logic level i suddenly remembered i had a Logic Probe from when i was at tech, this is powered from its own Batt supply but do i have to tap into the Neg Supply on the circuit to get a ground signal for the probe to work?