Difference between revisions of "8bit Printer Ports"

From CPCWiki - THE Amstrad CPC encyclopedia!
Jump to: navigation, search
(External Printer Ports)
(Internal 8bit Printer Ports/Mods)
Line 15: Line 15:
 
=== CPC Schneider International - 8bit Printer Port Mod ===
 
=== CPC Schneider International - 8bit Printer Port Mod ===
  
DIY from [[CPC Schneider International]] (issue 12'85), this solution uses joystick port pin 8 (or (keyboard?) pin 2, unclear?).
+
DIY from [[CPC Schneider International]] (issue 12'85, page 64), this solution uses joystick port pin 8 (or (keyboard?) pin 2, unclear?).
 
* For details see: [[CPCI 8bit Printer Mod]]
 
* For details see: [[CPCI 8bit Printer Mod]]
  
 
=== PC Amstrad International - 8bit Printer Port Mod ===
 
=== PC Amstrad International - 8bit Printer Port Mod ===
  
DIY from [[PC Amstrad International]] (issue 8/9'91, page 69), this solution uses PPI.Pin12 (same as the [[Happy Computer 8bit Printer Mod]]).
+
DIY from [[PC Amstrad International]] (issue 8/9'91, page 69-70), this solution uses PPI.Pin12 (same as the [[Happy Computer 8bit Printer Mod]]).
  
 
=== 8bit Printer Port in KC Compact ===
 
=== 8bit Printer Port in KC Compact ===

Revision as of 19:42, 4 August 2010

The CPC Printer Port has only 7bit data. Which is okay for english 7bit ASCII character sets, but not enough for 8bit character sets. Also, printing bitmap graphics usually requires 8bit data (though Amstrads own printers are probably working with 7bit).

Internal 8bit Printer Ports/Mods

Happy Computer 8bit Printer Port upgrade (DIY)

A good method to upgrade to full 8bit has been described in the german magazine "Happy Computer (Schneider Sonderheft) 2/85 and 4/86":

  • Disconnect the D7 pin from ground, and wire it to the PIOs Tape WR DATA pin instead (That is, Pin 12 of the 8255 chip).

Sharing that pin will cause no problems (as long as you do not attempt to send data to the tape drive and to printer at the same time). Of course, you will also have to customize your software, or BIOS ROM, or the BIOS jump vectors in RAM, in order to take advantage of the modification.

CPC Schneider International - 8bit Printer Port Mod

DIY from CPC Schneider International (issue 12'85, page 64), this solution uses joystick port pin 8 (or (keyboard?) pin 2, unclear?).

PC Amstrad International - 8bit Printer Port Mod

DIY from PC Amstrad International (issue 8/9'91, page 69-70), this solution uses PPI.Pin12 (same as the Happy Computer 8bit Printer Mod).

8bit Printer Port in KC Compact

The KC Compact uses the Bit5 of PPI Port C as 8th printer bit (this is same as the Happy Computer mod, see above). Although the 8th bit is a built-in feature, the KC Compact BIOS doesn't support it.

8bit Printer Port in Aleste 520EX

The Aleste 520EX includes an 8bit printer port, using PSG Ext Port B for data (which does not exist on the CPC), and PPI port C, Bit 4 for strobe (which would be Tape Motor in CPC). The Aleste doesn't have the normal CPC-style Printer Port at Port EFXXh. The BIOS functions are patched accordingly; including for supporting the 8th bit (unlike the CPC Plus and KC Compact, which do not support the 8th bit in BIOS functions).

8bit Printer Port in CPC Plus

In the CPC Plus, Bit 3 of CRTC Register 0Ch can be used as eighth printer bit. For compatibility to normal CPCs, this feature can be disabled by removing the 10kOhm resistor R30 on the mainboard (aka R130 in the schematic). See LK Links for more info. Although the 8th bit is a built-in feature, the CPC Plus BIOS doesn't support it.

External Printer Ports

Also, reportedly, the following external hardware exists:

  • KDS Communicator 104 (unclear if this is a "Modem" and/or a "Serial and Parallel interface") (in the latter case, "Parallel Interface" might refer to an 8bit printer port?)
  • 8bit Printer Port (Pride Utilities) (details)
  • 8bit Printer Port with Dual RS232 (Timatic Systems)
  • 8bit Printer Port with 16bit I/O port (HoneySoft) (see advert)

There's nothing else known about that hardware.