This I/O map applies to c16/116/+4 computers (c) 1990-1994 by Michael Stiller. Extension port pinouts (50 pin female) 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- CC BB AA Z Y X W V U T S R P N M L K J H F E D C B A 1 gnd A gnd 2 + 5V B C1 low 3 + 5V C BRESET -- 4 IRQ -- D RAS -- 5 R/W E I0 (clock0) 6 C1 high F A15 7 C2 low H A14 8 C2 high J A13 9 CS1 -- K A12 10 CS0 -- L A11 11 CAS -- M A10 12 MUX N A9 13 BA P A8 14 D7 R A7 15 D6 S A6 16 D5 T A5 17 D4 U A4 18 D3 V A3 19 D2 W A2 20 D1 X A1 21 D0 Y A0 22 AEC Z nc 23 extern Audio AA nc 24 02 (clock2) BB nc 25 gnd CC gnd Verified with the CBM Plus/4 User's Manual. Note:pins marked with '--' appear in the schematic as low active User port pinouts (24 pin male) 1 2 3 4 5 6 7 8 9 10 11 12 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- A B C D E F H J K L M N 1 gnd A gnd 2 +5V B P0 3 BRESET -- C RxD 4 P2 D RTS 5 P3 E DTR 6 P4 F P7 7 P5 H DCD 8 RxC J P6 9 ATN K P1 10 9V AC L DSR 11 9V AC M TxD 12 gnd N gnd Verified with the CBM Plus/4 User's Manual. Note:pins marked with '--' appear in the schematic as low active These pinouts are from the book: Wilhelm Besenthal/Jens Muus 'Alles ueber den Plus/4' Markt&Technik Verlag AG ISBN3-89090-410-6 Memory Map Overview from the CBM Plus/4 User's Manual Address RAM ROM $ffff End of RAM ROM Bank High $fffe IRQ Vector $fffc RES Vector $fffa NMI Vector $ff81 Kernal Jump Table $fd00 I/O Register/TED Register End if Basic RAM+1 $fc00 ROM-Banking routines $d800 Operating System $d000 Character Table $c000 Basic extensions $bfff ROM Bank Low $8000 BASIC $4000 start of basic ram if graphic $3fff graphic bitmap $2000 color map (graphic) $1c00 luminance (graphic) $1800 $1000 start of basic ram (no graphic) $0c00 character bytes (display) $0800 attribute bytes Detailed I/O Port Map as located in Plus/4 and similar CBM Computers (C16/116/+4) Most ports are not fully decoded by a chip called 7700-xx in the schematic, so they may appear copied on different memory locations. Addr $ Chip/Port Usage: $fd00-fd03 ACIA 6551A used for RS232 (for bits see +4 manual) $fd00 DATA port $fd01 STATUS port $fd02 COMMAND port $fd03 CONTROL port $fd04-fd07 ACIA copy $fd08-fd0b ACIA copy $fd0c-fd0f ACIA copy $fd10 PIO 6529B User Port PIO (P0-P7) Bit 2 (P2) is used to detect if play on cassette is pressed (CST sense) $fd11-fd1f PIO copies $fd20-fd2f free not connected $fd30 PIO 6529B Keyboard PIO Keyboard Matrix Connector P0 15 P1 18 P2 7 P3 12 P4 11 P5 10 P6 5 P7 1 $fd31-fd3f PIO copies $fd40-fdcf free not connected $fdd0-fddf ADDR CLK used for module select? in the schematic this is the clk/in for 4 D-FlipFlops located in the 74LS175 chip which generates the C1,C2 low/high signals $fde0-fdff free not connected * $fe00-fe1f free not connected * $fe20-fe3f free not connected * $fe40-fe5f free not connected * $fe60-fe7f free not connected * $fe80-fe9f free not connected * $fea0-febf free not connected * $fec0-fedf TIA 6523A if you have a CBM 1551 as device #9 then the TIA located in the paddle of you drive will appear at this location for details see $fee0-feff $fee0-feff TIA 6523A if you have a CBM 1551 as device #8 then the TIA located in the paddle of your drive will appear at this location $fee0 TIA PORT A (DATA) $fee1 TIA PORT B (STATUS) $fee2 TIA PORT C (HANDSHAKE) $fee3 TIA PORT A data direction register $fee4 TIA PORT B data direction register $fee5 TIA PORT C data direction register $fee6 not connected $fee7 not connected $fee8-feef TIA copy $fef0-fef7 TIA copy $fef8-feff TIA copy TIA Notes: The TIA 6523A is a triport interface adapter which is located in the paddle of the 1551 disk drives. The drivenumber causes the TIA to appear at the corresponding memory addresses as mentioned above. The address decoding stuff is done by another chip located in the 1551 paddle, called 8700-011 ? The TIA port a is used as direct 8 bit data connection between the computer and the drive. (It is called TCBM Bus in the 1551 schematic) The other TIA ports are used for other TCBM Bus signals (handshake etc.) They are connected as follows: Port bit used for B 0 status 0 B 1 status 1 C 6 DAV signal C 7 ACK signal The marked (*) port may be intended as additional drive locations,but they are not supported by the 1551 drives. (c) 1990-1994 by Michael Stiller. The informations here are given without warranty. May not be modified without permission. For comments,questions,donations etc. write to stille00@marvin.informatik.uni-dortmund.de