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what size should the stepper base and stepper game eprom be?

Chip used in the S2000 are:
         
Base, Key, Clear:  27C4002, 27C4096  256K x 16 bit
Game:                27C801, 27C080     1M x 8 bit
Version:              27C010 27C1001    128K x 8
SS:                    27C64 for 27C512  SS is a S+ Reel chip (requires a SB001000) depending on the speed of an original IGT S+ SS chip may have to copy them to a faster chip.
                         Do not use any offset if using a 27C512 in  a S2000

Speed should be 120ns or faster.

Foster...No Offset for a 64K SS chip burned to a 512K chip for use in the s2000 ? Do you use Copy and Fill? . Never tried it ...Not saying you are wrong...just sounds weird.

thanks for the reply  :3-

The lower address pins are identically placed in the 27c series which is why one can use larger capacity chips for applications requiring less memory. An offset is needed if the machine puts power to the higher address pins on a larger chip because that shifts the lower addresses to a higher page*. This happens when the hardware designers don't expect to use those pins and don't care whether they end up getting power or not.

I've never checked an S2000 but Foster knows these machines inside and out, so based on his post I'd say that it doesn't apply voltage to any of the upper address pins and hence no offset is needed.

Stat :31-


* Here's an example in base 10. You have code that ranges from address 00 to 99 and you're supposed to use a 100 unit chip. The machine expects a 100 unit chip and only reads addresses in the ones and tens places; it doesn't even know that hundreds exist.

You want to use a 1000 sized chip for whatever reason. Picture it as 10 pages of 100. In this example, when you put the chip in the machine, it accidentally sticks a 5 on the front so everything becomes 500 to 599 because the designers didn't care if the pins for the hundreds place got power or not.

The machine only expects to see two digit addresses from 00-99 and doesn't even know about the hundreds place. It can only see 100 addresses on your 1000 sized chip, but because of the flaw (voltage to the other pins) it's looking at 500-599 instead of 000-099. If you copy the "page" in 000-099 to 500-599 and the machine looks for the value at address 47, it will find it at (5)47 and read it as if it were at (0)47.

So in this example if you needed to use a larger chip from the same family (as long as the lower address pins weren't different) and you didn't know which (if any) upper pins were getting voltage, you could copy the data 10 times over into every possible "page" of 100 to be sure that the machine would see the 100 bits of data no matter what those other pins were doing. If you knew exactly which pins were getting voltage, you could put one copy of the data in precisely the right "page" and know that the machine would see it. If you knew that no upper address pins were getting voltage, you could put one copy of the data at the beginning of the chip.

I hope that helps explain what happens and why chip paging works, but is not always needed.

No copy and fill. I found this out by trying the offset of C000 and the chip failed, luckily it was one of the SST Flash 27SF512 (same pin outs as 27c512) EEPROM's
Tried no offset it worked perfectly.