The printer port supports one-directional 7bit data, strobe, and busy signals.
Data / Strobe
Port EFXX - Printer Port Output 74LS273 (7bit Data and Strobe) (W)
Bit 0-6 Printer Data (7bit) (0=Low, 1=High) Bit 7 Printer Strobe (0=High, 1=Low)
Busy (PIO.PortB.Bit6)
Port F5XX PIO Port B
Bit 0 VSYNC CRTC Vsync flag (1=VSYNC active) Bit 1-3 LK1-3 Distributor Code (see below) Bit 4 LK4 Desired Screen Refresh Rate (0=60Hz, 1=50Hz) (see below) Bit 5 /EXP External Input (used for external hardware only) Bit 6 BUSY Printer Busy flag (1=Busy, 0=Ready) Bit 7 RD DATA Tape Data Input
Pinouts
Upgrade to 8bit data
KC Compact Printer Port
The Printer Port in the KC Compact is fully compatible with the CPCs Printer Port, and includes some additional features:
- Port EFxxh is CIO Port A, by default configured as Output, with inverted polarity on bit7 (same as on CPC). However, CIO Port A could be reprogrammed by software (for example: making it an Input, or disabling the bit7 inversion)
- The 8th Printer bit connects to Bit5 of PIO Port C (same as the Happy Computer 8bit Printer Port mod)
- The "TEST" Feature of the KC Compact BIOS allows to boot the computer remotely via some kind of "network" connection, which connects to some of the CIO Port A signals
Aleste 520EX Printer Port
The Aleste 520EX is not compatible with the CPCs Printer Port (it's having other hardware mapped to EFXXh). Aside from the compatibility problem it's better than the CPCs port: Data is 8bit bi-directional.