How to program an EEPROM?
How to program an EEPROM?
(OP)
I have a multiplexer circuit that I built to control the main circuit but it makes the circuit very large because of large numbers of dicreet ICs. I want to do the timing by EEPROM but I don't know how to program one and what do I need other than the EEPROM IC. Please advise!





RE: How to program an EEPROM?
TTFN
RE: How to program an EEPROM?
You don't say what the "main circuit" actually is. As always with these sort of problems we need maximum information to be able to help.
The best solution to reducing large amounts of low level logic is to use a programmable set of gates known in simple terms as an FPLA (field programmable logic array) or PLD (programmable logic device), however these require a more complex programming setup.
EEPROMS can be used to perform the function of logic arrays provided you understand exactly how many inputs and outputs you require and that these can be fitted within the size of the EEPROM. To design such a device the input functions would be applied to the address lines and the normal data outputs become your custom logic outputs.
The downside to using an EEPROM (or any other memory array)is that you have to work out a "map" where you consider every single combination of input and output that can occur for your required logic function. This may mean that you could have to program every single location, and using even a small modern EEPROM that's a lot of combinations!
Don't forget that your average EEPROM is not capable of driving a large number of logic loads from its outputs, so you may still need some buffering.
Hope that helps,
Brian
RE: How to program an EEPROM?
The modern EPLD- Erasable Programmable Logic Device is by far superior to an EPLA, since it provides registers and multiple states within the device. You would need additional registers to barely duplicate the simplest EPLD functions with an EPLA. An EPLD is also designed to drive multiple devices as well as provide bidirectional and tristate outputs.
TTFN
RE: How to program an EEPROM?
RE: How to program an EEPROM?
And I did a contract there!
joecad
RE: How to program an EEPROM?
i also made sequential state machines by adding to this PROM an external register (like '374) to hold the state vector.
worked like a champ. those PROMs i could program by "hand" with a little board i made. toggle switches for the desired 8-bit value and a couple of rotary sixteen-position hex coded switches to set the address, and a push button to drive the programming pulse. crude but very effective.
that part is probably long dead, but the point is that if you look at the data sheet you'll often see that the actual act of programming can be done with some simple circuits. and as was said above, its great to have flexibility in your design. i love programmable hardware.
RE: How to program an EEPROM?
As IRSTUFF wrote, FPGA is a perfect solution -- what he
forgot, it may not be the cheapest. For some FPGA you may
have to shell out many thousand $$$-s for software to program it efficiently.
<nbucska@pcperipherals.com>
RE: How to program an EEPROM?
http://www.coolpld.com/index.shtml
The devices can be programmed while in circuit through a few dedicated serial pins. I have designed my own cable with some added capabilities to program seperate serial non volatile eeroms. If interested, I can email schematics and an example of software to program serial memory using pins not used by Xilinx software.
FPGA's are another solution with more capability but usually require a serial eeprom and do a boot sequence to transfer this data to that logic memory at power up. The same Xilinx software will handle many of these. Altera and others in the market have similar offerings and development software.
Are you asking about standard parallel EPROM style EEPROMS?