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Chapter 4: Programming Set Up
FirmwareandsoftwarefunctiondescriptionsfortheNCR5972Retail
Displayarepresentedinthischapter.
Host/Retail Display Command Interface
TheRetailDisplayacceptstwotypesofdata:displaydataand
commanddata.Ifabytereceivedfromthehostisanycharacterexcept
theESC(0x1B)character,itisprocessedasacharacteranddisplayed
ontheRetailDisplay.IfanESCcharacter(0x1B)isreceived,the
subsequentbyte(s)is
processedasacommand.Ifthesubsequentbyte
isaninvalidcommanditisignored.IfanESCisreceived,butno
commandbyteisreceivedimmediately,thefirmwarewaitsforeverif
needbeandusesthenextreceivedbyte(s)tocompletethecommand.
Note: Eachcommandconsistsofatleast
twobytes.Thefirstbyte
(0x1B)isacommandidentifierindicatingthenextbyte(s)isa
commandbyte.Thecommandbytemaybefollowedbyparameter
ordatabytesdependingonthecommand.AlsonotethattheESC
charactercanbedisplayedbyusingtheDisplayESCCharacter
command.