Jump to content

Eprom chip questions. Nes snes repros.


Recommended Posts

Ok I have ordered a bunch of stuff to start making nes and snes repros. I have done a lot of reading and was wondering if someone could explain some of these numbers to me on eproms.


I have read that 27c are what you need for nes. Nes is 28 pins. Wondering if a chip such as these would work.


AMD AM27C128-200DC

AMD AM27C256-200DI


AMD AM is manufatcurer


27 "I will assume series"

c= cmos = Complimentary Metal Oxide Semiconductor

128 or 256 is the size

200 is the speed. This is the maximum delay time between the inputting of an address and the outputting of the data to the ports of the memory chips


Whats really confusing me is the DC DI stuff at ends, do these matter?


So two chips are needed one for the prg and one for the chr. Some are 128 some are 256. I read you can use a 256 for 128 but file has to be duplicated to fill the chip.


Basically I read nes should be at least 150 on the speed.


So too sum it up will these work for nes repros? What are best speeds and what are the DC DI at ends mean?


I have not looked into snes chips yet.

Link to comment
Share on other sites

yes DC is commercial and DI is industrial, the latter is certified to handle more extreme temperatures otherwise the same


and yes the lower the number the faster the chip, if you need to go faster or not I am unsure

  • Like 1
Link to comment
Share on other sites

  • 3 months later...
  • 3 years later...

Hmmm is appears the higher the number on speed the slower the chip...


A bit late replying on this, but yes, and for the record:


The 'speed' of these memory chips is usually quoted as an access time. A -150 signifies a memory device whose contents can be accessed in 150ns. A -200 takes 200ns for the data output to be valid.


Conversely, microprocessors are specified to work at a particular clock rate, for example the Z80 ran with a clock rate of 2.5 MHz, the Z80A runs at 4MHz, the Z80B at 6MHz.

Edited by Derek Andrews
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...