Hello world/Line printer: Difference between revisions

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\ memory mapped I/O addresses for the printer port
HEX
B02E CONSTANTconstant SCSRscsr \ serial control status register
B02F CONSTANTconstant SCDRscdr \ serial control data register
DECIMAL
 
: printer-emit ( char -- ) \ output 'char' to the printer serial port
BEGINbegin SCSRscsr C@ 80 ANDand UNTILuntil \ loop until the port shows a ready bit
SCDRscdr C! \ C! (char store) writes a byte to an address
20 ms ; \ delay to prevent over-runs
 
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