Lets start with using I/O-pins 0-7 for the databus, then...
Now, the address bus is a bit more difficult, and you probably also want to reserve a pin for the OE signal.
You could hook up a couple of 74HC595 serial-in-parallel-out shift-registers and just clock out new addresses on them. That should be an easy enough way to handle the addresses.
A slightly more difficult way to hook it up, but which will allow you to read out the data quicker is to use a couple of counters.
Here's a pickture of how a 2764 was accessed on an old PDA. http://totallytrygve.com/computer.php?item=1&picture=0&page=2
Use one I/O to reset the counter, then another to clock it until it reaches the address you want.
(In that particular setup, the I/O-pin used to clock also functions as the A0 signal)
If the thought of clocking through 256K addresses sounds a bit slow, stick in a 74HC595 or two for the higher addresses, and use them as some sort of 'page address'.
Have fun!
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Don't visit my new website...
· Mind you, you're on about an EPROM (Erasable) and not an EEPROM (Electrically Erasable.)· So, you can't use it like an NVRAM.· Once·data·is·written at an address, it'll keep that data and cannot be re-written/re-programmed.· You can, of course, read from any address as much as you like.·
· If you want to be able to re-program it, then you'll need to get an EPROM Eraser (uses ultra-violet light.)
Comments
(Programming it may be a bit of a trick)
How large blocks of data do you need to access in one go, and how many pins can you set aside for this task?
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Don't visit my new website...
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lets see what this does... KA BOOM (note to self do not cross red and black)
Sounds like a good enough reason to tinker...
Lets start with using I/O-pins 0-7 for the databus, then...
Now, the address bus is a bit more difficult, and you probably also want to reserve a pin for the OE signal.
You could hook up a couple of 74HC595 serial-in-parallel-out shift-registers and just clock out new addresses on them. That should be an easy enough way to handle the addresses.
A slightly more difficult way to hook it up, but which will allow you to read out the data quicker is to use a couple of counters.
Here's a pickture of how a 2764 was accessed on an old PDA.
http://totallytrygve.com/computer.php?item=1&picture=0&page=2
Use one I/O to reset the counter, then another to clock it until it reaches the address you want.
(In that particular setup, the I/O-pin used to clock also functions as the A0 signal)
If the thought of clocking through 256K addresses sounds a bit slow, stick in a 74HC595 or two for the higher addresses, and use them as some sort of 'page address'.
Have fun!
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Don't visit my new website...
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
lets see what this does... KA BOOM (note to self do not cross red and black)
· If you want to be able to re-program it, then you'll need to get an EPROM Eraser (uses ultra-violet light.)