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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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How do you get an MCU design to market quickly? Programming File for 27C64 Eprom Hello, Was wondering if someone that has had some experience in creating a BIN or HEX file suitable for a 27C64 Eprom could point epom in the right direction re creating 2c764 file that would allow the above Eprom to control the output of its data lines D0 – D7 so that it will switch the lines either high or Low i.

27C64 Datasheet pdf – 64K (8K x 8) CMOS EPROM – Microchip

I don’t mean to take up all of your time but i would be really interested in hearing more about the microprocessor option elrom 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. The on the third schematic is periodicaly pulsing the latch signal so the switches are read in.

Would it be possible for you to take a quick look and tell me where, looking at the diagram i would enter the data to have “01” selected on the Push Buttons and have “DO” pin 11 pulled low on the Eprom output? Bin file itself as this is what i use to burn the Eproms but will wait to see if you think this will epgom the way it should before i attempt to complete the file.

Measure the voltages on all the Address lines and write down whether they are high or low as a binary number, for example: You will see distinctly different voltages on the pins and they will almost certainly be very close to 0V or 5V.

It is very easy to convert the bit pattern from binary to hexadecimal.

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. The Channel Change module runs on 12V DC fed from the rack supply and if i can fprom this to power the Logic probe would this give me the ground eprlm for the probe to check the status of the lines?


I would guess the data ends up in a PLL circuit elsewhere in the radio so the equal sized jumps in EPROM data would suggest that the same frequency spacing exists between each channel 10Khz, 25KHz or whatever.

Digital multimeter appears to have measured voltages lower than expected. Programming File for 27C64 Eprom It is possible for data to be duplicated and I would expect the vast majority of the addresses to be empty in this kind of application. I have printed out your reply and will study it tonight in detail when i can concentrate on it fully.

After a while, when you have got used to thinking in hexadecimal it all falls into place, it’s easier than it looks.

Bin files i have seen before. If you know the channel frequencies it should be easy to work out, it’s likely that a change of one count in the EPROM data makes a difference of one channel frequency so if you know what the channels are, it should be simple math to reverse engineer it back to the EPROM data you need.

27C64 – 27C64 64K EPROM Datasheet

Thanks for your Help, Brian. PV charger battery circuit 4.

This then gives me a set of ascending Location Numbers for the data and and what looks eprpm descending data to go in those locations. I have the Eproms for the TX and RX modules correctly burned with programming files provided by the equipment manufacturer Tait but i am lost as to how to create a BIN or Hex file from scratch to get the Channel Change Eprom to output the correct switching via its Data out lines. The device is a Remote Channel Change module for a Repeater rack and allows remote selection of channels in the TX and Rx modules by pulling various data lines in the same chip installed in the modules either high or low depending on the channel selected.

It would be useful to note this because you may be able to use it to calculate new channel frequencies. Because of the strange way the EPROM address pins are connected, the input digits are reversed so if you want channel 10 you use address 01 instead. You could replace the whole module with just a handful of modern components, in fact you could replace the entire selector AND channel EPROM board with a simple micro and a display driver circuit.

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.


Would you have a minute eprrom take a look at a file i have produced in regards this. The “External Interface” on the left Hand top is where the Channel Change eprom output connects to directly and you can manually select any of the channels that have been previously programmed via the Tait Software into the radio’s own Eprom, via the 8 DIP switches.

After i asked you about using the DVM to check 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? 27c6 complex number interms of the other 6. Programming File for 27C64 Eprom I’m back again epro, 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 wanted was any sudden movements!

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.

I’m more or less upright again now so “on with the work! For example, if you wanted EPROM channel 10 to produce an output of you would first reverse the channel digits and use address 01, then split the 8 bit output you want into two becomes then convert each to hexadecimal to find the number to store in the EPROM.

Part and Eeprom Search. It’s better to share your questions and answers on Edaboard so we can all benefit from each others experiences. I’m suspicious of the maximum voltage for logic 1 being 2. Last edited by tait ; 21st April at Dec 242: What i would like to do is check that the unit is sending the correct signals via the Data lines to switch the Eprom on the Radio Channel Board to select the correct channel.