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I believe the 27C200 to be equivalent to the 27C2100 (and the 27C400 equivalent to the 27C4100). These EPROMs should be available through some distributors. They are different from the 27C2048 and the 27C4096 because the 272048/274096 are strictly 16-bit, while the 27C2100 and the 27C4100 can be switched between 8-bit and 16-bit (there's a BYTE' line that selects Words [16-bit] if HIGH and Bytes [8-bit] if low - when in 8-bit mode, bits 8-14 on the data bus go to high-impedance and bit 15 allows you to choose the upper or lower byte of the address to be spit out of bits 0-7). If you can't find these chips, Jameco has a 27C160, which has the same pinout, except that it's a 42-pin chip instead of a 40-pin chip, so it has 2 additional pins on the left side (the side with the "U" indention). These pins are extra address pins - you could probably just ground them to make it backwards compatible with the other versions. (Note: some surface mount dual inline versions of the 27C160 are 44-pin, having 2 additional pins added to the left side that are not found on the DIP version - these 2 pins have no connection). |
