Dynamic Shift Registers - Bitsavers - Trailing-Edge

ROM Code ConvertersMM4220EK/MM5220EKBCDIC-to-EBCDIC and ASCII-to-EBCDIC code converters3:3:~NNom~.......3:3:U'1NNom~general descriptionTheMM4220EK/MM5220EK isa 1024-bitread onlymemory that has been programmed to convertboth Binary Coded Decimal Interchange Code(BCDIC) and the American Standard Code forInformation I nterchange (ASCII) to Extended BinaryCoded Decimal Interchange Code (EBCDIC).The BCDIC-to-EBCDIC converter is located in thefirst 64 8-bit bytes of the ROM. The unused paritycheck bit (the most significant input BCDIC bit) isalways a "0".The ASCII-to-EBCDIC converter is located in thesecond 64 8-bit bytes of the ROM. Thus, the inputASCII code in addresses 64 through 127 has a "1"in the most significant (A7) bit which is used withthe selection logic. The resulting 6-bit ASCII inputis for display-only upper case and numericalcodes, since it will not accept the control commandsor the lower case characters.device characteristicsFor full electrical, environmental and mechanicaldetails, refer to the MM4220/MM5220 1024-bitread only memory data sheet.typical applicationconnection diagram-12V----------------+~t_....,b, 1b, 1.5V--+--------------I--II-4---_--A,8,6.8K,TYPICAL,B LINESGATES OM740(}A, 14 V,,A, 13A, 11b, 4A,8,8, 11 A,b, Sb, Ab, 8"CODE"A,11A,10'" "A, 18MM4220EK/MM52Z0EK8,s,s,, S,~8, 10 A,8,8, 18 A,8, 17V""8, 16A,MODECONTROLl.OK,TYPICAL,1UNESV"+12V-----.~t--"""I12tA,"CHIP ENABLE ___..J10 j.:8::.-, ------11---1111"8;;..' ---~t--IOlL/TTL LOGIC8, 10 158, 11 14 A,V" 12 13TOP VIEWCHIPENABLEtMOOE CONTROL ------'Logic LeulsDTlfTTl (except at MQS/ROM Interface)logic "l",+!iV, nom. Logic "Q",glound, nom.MOS/ROM Inputs & OutputlogIc "l",more neptive. logic "D",more positlYetMode COntrol = logic "0"AB= llJgic"l"·Chlp Enable = Logic "1" to obtain outputs193