Difference between revisions of "8bit Printer Port (Paul Bauriedl)"

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This 8bit Printer Port expansion is described in the book [[Maschinenspracheprogramme und Hardware-Erweiterungen für Schneider CPC's]] by [[Paul Bauriedl]]. It only connects to the centronics port of the CPC and doesn't require internal modifications.
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This [[8bit Printer Ports||8bit Printer Port]] expansion is described in the book [[Maschinenspracheprogramme und Hardware-Erweiterungen für Schneider CPC's]] by [[Paul Bauriedl]]. It only connects to the centronics port of the CPC and doesn't require internal modifications.
  
 
== Description ==
 
== Description ==

Revision as of 09:10, 27 February 2010

This |8bit Printer Port expansion is described in the book Maschinenspracheprogramme und Hardware-Erweiterungen für Schneider CPC's by Paul Bauriedl. It only connects to the centronics port of the CPC and doesn't require internal modifications.

Description

In this design, only the lower 4 bits of the printer port are directly connected to the printer. The upper 4 bits are generated with the help of a latch (LS 75). If you want to print, you have to send the upper 4 bits in D0-D3 and set D4 to high to buffer the values in the latch which is connected to D4-D7 of the printer. The rest of the data can be sent by the normal printer routine of the firmware (with D4 set to 0 to disable the latch).

Schematics

8bitPrinterPortPaulBauriedl.png]

Listing

10 ;Patch fuer 8-bit Centronics
20 ;direkt unter HIMEM (+Floppy)
30 ;
40 indjmp: 	equ	#bdf1
50 ;
60		org	42619-40
70 ;Initialisieren
80 		ld	hl, (indjmp+1)
90		ld	(retour+1),hl
100		ld	hl,bit0
110		ld	(indjmp+1),hl
120		ret
130 ;
140 ;neue Ausgaberoutine
150 ;ist ueber Druckerindirektion
160 ;#BDF1 eingeschleift
170 ;
180 bit0:	ld	b,#ef
190		push	af
200		srl	a
210		srl	a
220		srl	a
230		srl	a
240		out	(c),a
250		set	4,a
260		out	(c),a
270		res	4,a
280		out	(c),a
290		pop	af
300		and	#0f
310 ;Jump wird beruecksichtigt
320 ;je nach System!
330 retour:	jp	#07f8