Epson LQ 1050 Technical Manual - Page 205
HM27256G-25, EP-ROM
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A.1.4 HM27256G-25 EP-ROM This EP-ROM is a ultra-violet erasable and electrically programmable ROM of 32 K-bytes. REV.-A Features q Capacity of 32768 words X 8 bits q 1/0 with TTL compatible q Power supply +5V DC q Access time 250 ns q 28 pins (DIP) Terminal Functions . AO - Al 4 Input address q = Chip enable q OE Output enable q DO - D7 Input/Output data Vpv 1 4 !2 2 A7 3 46 1. A5 5 A4 6 A3 7 A2 e A! 9 A o 10 00 11 D 1 12 02 13 GND 14 26 Vcc n A14 26 413 2S A 8 2(, A 9 23 A It 22 TE 21 AIO 1 9 D7 16 06 17 05 16 04 15 03 Figure A-10. HM27256G-25 Pin Diagram Vcc o GND Vpp 6F- Output Enable ?-iF- Chip Enable Y- Decode Dato Out Put Do - D7 output Buffer - 1 Y- Select Address lnpW 'AO - Ai4 X - Decode E :f, Memory Ce II Mat rix 262144 bit Figure A-1 1. HM27256G-25 EP-ROM Block Diagram A-1 9