; Commodore plus/4 and
; Commodore 16 Memory Map
;
; V1.1 9 Dec 1994
;
Label Hex Addr. Decimal Loc. Description
PDIR $0000 0 7501 on-chip data-direction register
PORT $0001 1 7501 on-chip 8-bit Input/Output register
SRCHTK $0002 2 Token 'search' looks for (run-time stack)
ZPVEC1 $0003-0004 3-4 Temp (renumber)
ZPVEC2 $0005-0006 5-6 Temp (renumber)
CHARAC $0007 7 Search character
ENDCHR $0008 8 Flag: scan for quote at end of string
TRMPOS $0009 9 Screen column from last TAB
VERCK $000A 10 Flag: 0 = load 1 - verify
COUNT $000B 11 Input buffer pointer / No. of subsctipts
DIMFLG $000C 12 Flag: Default Array DIMension
VALTYP $000D 13 Data type: $FF = string $00 = numeric
INTFLG $000E 14 Data type: $80 = integer, $00 = floating
DORES $000F 15 Flag: DATA scan/LIST quote/garbage coll
SUBFLG $0010 16 Flag: subscript ref / user function coll
INPFLG $0011 17 Flag: $00 = INPUT, $43 = GET, $98 = READ
TANSGN $0012 18 Flag TAN siqn / comparison result
CHANNL $0013 19 Flag: INPUT prompt
LINNUM $0014-0015 20-21 Temp: integer value
TEMPPT $0016 22 Pointer: temporary string stack
LASTPT $0317-0018 23-24 Last temp string address
TEMPST $0019-0021 25-33 Stack for temporary strings
INDEX1 $0022-0023 34-35 Utility pointer area
INDEX2 $0024-0025 36-37 Utility pointer area
RESHO $0026 38
RESMOH $0027 39
RESMO $0028 40
RESLO $0029 41
$002A 42
TXTTAB $002B-002C 43-44 Pointer: start of BASIC text
VARTAB $002D-002E 45-46 Pointer: start of BASIC variables
ARYTAB $002E-0030 47-48 Pointer: start of BASIC arrays
STREND $0031-0032 49-50 Pointer: end of BASIC arrays (+1)
FRFTOP $0033-0034 51-52 Pointer: bottom of string storage
FRESPC $0035-0036 53-54 Utility string pointer
MEMSIZ $0037-0038 55-56 Pointer: highest address used by BASIC
CURLIN $0039-003A 57-58 Current BASIC line number
TXTPTR $003B-003C 59-60
FNDPNT $003D-003F 61-62
DATLIN $003F-0040 63-64 Current DATA line number
DATPTR $0041-0042 65-66 Pointer: Current DATA item address
INPPTR $0043-0044 67-68 Vector: INPUT routine
VARNAM $0045-0046 69-70 Current BASIC variable name
VARPNT $0047-0048 71-72 Pointer: Current BASIC variable data
FORPNT $0049-004A 73-74 Pointer: Index variable for FOR/NEXT
OPPTR $0048-004C 75-76
OPMASK $004D 77
DEFPNT $004E-004F 78-79
DSCPNT $0050-0051 80-81
$0052 82
HELPER $0053 83
JMPER $0054 84
SIZE $0055 85
OLDOV $0056 86
TEMPF1 $0057 87
HIGHDS $0058-0059 88-89
HIGHTR $005A-005B 90-91
$005C 92
LOWDS $005D-005E 93-94
LoWTR $005F 95
EXPSGN $0060 96
FACEXP $0061 97 Floating-point accumulator #1: exponent
FACHO $0062 98 Floating accum. #1: mantissa
FACMOH $0063 99
FACMO $0064 100
FACLo $0065 101
FACSGN $0066 102 Floating accum. #1: sign
SGNFLG $0067 103 Pointer: series evaluation constant
BITS $0068 104 Floating accum. #1: overflow digit
ARGEXP $0069 105 Floating-point accumulator #2: exponent
ARGHO $006A 106 Floating accum. #2: mantissa
ARGMOH $006B 107
ARGMO $006C 108
ARGLO $006D 109
ARGSGN $006E 110 Floating accum. #2: sign
ARISGN $006F 111 Sign comparison result: accum. #1 vs #2
FACOV $0070 112 Floating accum. #1. low-order (rounding)
FBUFPT $0071-0072 113 Pointer: cassette buffer
AUTINC $0073-0074 115-116 Increment value for auto (0 = off)
MVDFLG $0075 117 Flag if 10K hires allocated
KEYNUM $0076 118
KEYSIZ $0077 119
SYNTMP $0078 120 Used as temp Eor indirect loads
DSDESC $0079-0078 121-123 Descriptor for DSS
TOS $007C-037D 124-125 Top of run time stack
TMPTON $007E-007F 126-127 Temps used by music (tone & volume)
VOICNO $0080 128
RUNMOD $0081 129
POINT $0082 130
GRAPHM $0083 131 Current graphic mode
COLSEL $0084 132 Current color selected
MC1 $0085 133 Multicolor 1
FG $0086 134 Foreground color
SCXMAX $0087 135 Maximum # of columns
SCYMAX $0088 136 Maximum # of rows
LTFLAG $0089 137 Paint-left flag
RTFLAG $008A 138 Paint-Right flag
STOPNH $008B 139 Stop paint if not BG (Not same Color)
GRAPNT $008C-008D 140-141
VTEMP1 $008E 142
VTEMP2 $008F 143
STATUS $0090 144 Kernal I/O status word: ST
STREY $0091 145 Flag: STOP key / RVS key
SPVERR $0092 146 Temp
VERFCK $0093 147 Flag: 0 = load, 1 = verify
C3PO $0094 148 Plag: serial bus - output char buffered
BSOUR $0095 149 Buffered character for serial bus
XSAV $0096 150 Temp for basin
LDTND $0097 151 # of open files / index to file table
DFLTN $0098 152 Default input device (0)
DFLTO $0099 153 Default output (CMD) device (3)
MSGFLG $009A 154 Flag: $80 = direct mode $00 = program
SAL $009B 155 Tape pass 1 error log
SAH $009C 156 Tape pass 2 error log
EAL $009D 157
EAH $009E 158
T1 $009F-00A0 159-160 Temp data area
T2 $00A1-00A2 161-162 Temp data area
TIME $00A3-00A5 163-165 Real-time jiffy clock (approx) 1/60 sec
R2D2 $00A6 166 Serial bus usage (EOI on output)
TPBYTE $00A7 167 Byte to be written/read on/off tape
BSOUR1 $00A8 168 Temp used by serial routine
FPVERR $00A9 169
DCOUNT $00AA 170
FNLEN $00A8 171 Length of current file name
LA $00AC 172 Current logical fiie number
SA $00AD 173 Current seconda.y address
FA $00AE 174 Current device number
FNADR $00AF-00B0 175-176 Pointer: current file name
ERRSUM $00B1 177
STAL $00B2 178 I/O start address
STAH $00B3 179
MEMUSS $00B4-00B5 180-181 Load ram base
TAPEBS $00B6-00B7 182-183 Base pointer to cassette base
TMP2 $00B8-00B9 184-185
WRBASE $00BA-00BB 186-187 Pointer to data for tape writes
IMPARM $00BC-00BD 188-189 Pointer to immediate string for primms
FETPTR $00BE-00BF 190-191 Pointer to byte to be fetched in bank fetc
SEDSAL $00C0-00C1 192-193 Temp for scrolling
RVS $00C2 194 RVS field flag on
INDX $00C3 195
LSXP $00C4 196 X position at start
LSTP $00C5 197
SFDX $00C6 198 Flag: shift mode for print
CRSW $00C7 199 Flag: INPUT or GET from keyboard
PNT $00C8-00C9 200-201 Pointer: current screen line address
PNTR $00CA 202 Cursor column on current line
QTSW $00CB 203 Flag: editor in quote mode, $00 = no
SEDT1 $00CC 204 Editor temp use
TBLX $00CD 205 Current cursor physical line number
DATAX $00CE 206 Temp data area
INSRT $00CF 207 Flag: insert mode, >0 = # INSTs
$00D0-$00D7 208-215 Area for use by speech software
$00D8-00E8 216-232 Area for use by application software
CIRSEG $00E9 233 Screen line link table / editor temps
USER $00EA-00EB 234-235 Screen editor color IP
KEYTAB $00EC-00ED 236-237 Key scan table indirect
TMPKEY $00EE 238
NDX $00EF 239 Index to keyboard queue
STPFLG $00F0 240 Pause flag
TO $00F1-00F2 241-242 Monitor ZP storage
CHRPTR $00F3 243
BUFEND $00F4 244
CHKSUM $00F5 245 Temp for checksum calculation
LENGTH $00F6 246
PASS $00F7 247 Which pass we are doing str
TYPE $00F8 248 Type of block
USE4DY $00F9 249 (B.7 = 1)=> for wr, (B.6 = 1)=> for rd
XSTOP $00FA 250 Save xreg for quick stopkey test
CURBNK $00FB 251 Current bank configuration
XoN $00FC 252 Char to send for a x-on (RS232)
XoFF $00FD 253 Char to send for a x-off (RS232)
SEDT2 $00FE 254 Editor temporary use
LOFBUF $00FF 255
FBUFFR $0100-$010F 256-271
SAVEA $0110 272 Temp Locations for
SAVEY $0111 273 ... for Save and
SAVEX $0112 274 ... Restore
COLKEY $0113-0122 275-289 Color/luminance table in RAM
SYSSTK $0124-01FF 291-511 System stack
BUF $0200-0258 512-606 Basic/monitor input buffer
OLDLIN $0259-025A 601-602 Basic storage
OLDTXT $025B-025C 603-604 Basic storage
$025D-02AC 605-684 BASIC/DOS INTERFACE AREA
XCNT $025D DOS loop counter
PNBUFR $025E-026D Area for filename
DOSF1L $026E DOS filename 1 length
DOSDS1 $026F DOS disk drive 1
DOSF1A $0270-0271 DOS filename 1 addr
DOSF2L $0272 DOS filename 2 length
DOSDS2 $0273 DOS disk drive 2
DOSF2A $0274-0275 DOS filename 2 addr
DOSLA $0276 DOS logical address
DOSEA $0277 DOS phys addr
DOSSA $0278 DOS secordary address
DOSDID $0279-027A DOS disk identifier
DIDCHK $0278 DOS DID flag
DOSSTR $027C DOS output string buffer
DOSSPC $027D-02AC Area used to build DOS string
Graphics Variables
XPOS $02AD-02AE 685-686 Current x position
YPOS $02AE-02B0 687-688 Current y position
XDEST $02B1-02B2 689-690 X coordinate destination
YDEST $02B3-02B4 691-692 Y coordinate destination
XABS $02B5-02B6 693-694
YABS $02B7-0288 69S-696
XSGN $02B9-02BA 697-69B
YSGN $02BB-028C 699-700
FCT1 $02BD-02BE 701-702
FCT2 $02BF-02C0 703-704
ERRVAL $02C1-02C2 705-706
LESSER $02C3 707
GREATR $02C4 708
ANGSGN $02C5 709 Sign of angle
SINVAL $02C6-02C7 710-711 Sine of value of angle
COSVAL $02C8-02C9 712-713 Cosine of value of angle
ANGCNT $02CA-02CB 714-715 Temps for angle distance routines
Start of multiply defined area #1
$02CC 716 Placeholder
BNR $02CD 717 Pointer to begin no.
ENR $02CE 718 Pointer to end no.
DOLR $02CF 719 Dollar flag
FLAG $02DO 720 Comma flag
SWE $02D1 721 Counter
USGN $02D2 722 Sign exponent
UEXP $02D3 723 Pointer to exponent
VN $02D4 724 # of digits before decimal point
CHSN $02D5 725 Justify flag
VF $02D6 726 # of pos before decimal point (field)
NF $02D7 727 # of pos after decimal point (field)
POSP $02D8 728 +/- flag (field)
FESP $02D9 729 Exponent flag (field)
ETOF $02DA 730 Switch
CFORM $02D8 731 Char counter (field)
SNO $02DC 732 Sign no.
BLFD $02DD 733 Blank/star flag
BEGFD $02DE 734 Pointer to beginning of field
LFOR $02DF 735 Length of format
ENDFD $02E0 736 Pointer to end of field
XCENTR $02CC-02CD 716-717
YCENTR $02CE-02CF 718-719
XDIST1 $02D0-02D1 720-721
YDIST1 $02D2-02D3 722-723
XDIST2 $02D4-02D5 724-725
YDIST2 $02D6-02D7 726-727
$02D8-02D0 728-729 Placeholder
COLCNT $02DA 730 Characters column counter
ROWCNT $02DB 731 Characters row counter
STRCNT $02DC 732
Start of multiply defined area #2
XCORD1 $02CC-02CD 716-717
YCORD1 $02CE-02CF 718-719
BOXANG $02D0-02D1 720-721 Rotation angle
XCOUNT $02D2-02D3 722-723
YCOUNT $02D4-02D5 724-725
BXLENG $02D6-02D7 726-727 Length of a side
XCORD2 $02D8-02D9 728-729
YCORD2 $02DA-02DB 730-731
XCIRCL $02CC-02CD 716-717 Circle center, x coordinate
YCIRCL $02CE-02CF 718-719 Circle center, y coordinate
XRADUS $02D0-02D1 720-721 X radius
YRADUS $02D2-02D3 722-723 Y radius
ROTANG $02D4-02D5 724-725 Rotation angle
ANGBEG $02D8-02D9 728-729 Arc angle start
ANGEND $02DA-02DB 730-731 Arc angle end
XRCOS $02DC-02DD 732-733 X radius * cos (rotation angle)
YRSIN $02DE-02DF 734-735 Y radius * sin (rotation angle)
XRSIN $02E0-02E1 736-737 X radius * sin (rotation angle)
YRCOS $02E2-02E3 738-739 Y radius * cos (rotation angle)
Start of multiply defined area #3
$02CC 716 Placeholder
KEYLEN $02CD 717
KEYNXT $02CE 718
STRS2 $02CE 719 String length
GETTYP $02D0 720 Replace string mode
STRPTR $02D1 721 String position counter
OLDBYT $02D2 722 Old bit map byte
NEWBYT $02D3 723 New string or bit map byte
$02D4 724 Placeholder
XSI2E $02D5-02D6 725-726 Shape column length
YSIZE $02D7-02D8 727-728 Shape row length
XSAVE $02D9-02DA 729-730 Temp for column length
STRADR $02D8-02DC 731-732 Save shape string descriptor
BITIDX $02DD 733 Bit index into byte
SAYSIZ $02DE-02E1 734-737 Temporary work locations
CHRPAG $02E4 740 High byte addr of char ROM for char cmd
LITCNT $02E5 741 Temp for gshape
SCALEM $02E6 742 Scale mode flag
WIDTH $02E7 743 Double width flag
FILFLG $02E8 744 Box fill flag
BITMSK $02E9 745 Temp for bit mask
NUMCNT $02EA 746
TRCFLG $02EB 747 Flags trace mode
T3 $02EC 748
T4 $02ED-02EE 749-750
VTEMP3 $02EF 751 Graphic temp storage
VTEMP4 $02F0 752
VTEMP5 $02F1 753
ADRAY1 $02E2-02F3 754-755 Ptr to routine: convert float to integer
ADRAY2 $02F4-02F5 756-757 Ptr to routine: convert integer to float
BNKVEC $02FE-02FF 766-767 Vector for function cartridge users
IERROR $0300-0301 768-769 Indirect Error (Output Error in .X)
IMAIN $0302-0303 770-771 Indirect Main (System Direct Loop)
ICRNCH $0304-0305 772-773 Indirect Crunch (Tokenization Routine)
IOPLOP $0306-0307 774-775 Indirect List (Char List)
IGONE $0308-0309 776-777 Indirect Gone (Character Dispatch)
IEVAL $030A-0303 778-779 Indirect Eval (Symbol Evaluation)
IESCLK $030C-030D 780-781 Escape token crunch
IESCPR $030E-030F 782-783
IESCEX $0310-0311 784-785
ITIME $0312-0313 786-787
CINV $0314-0315 7B8-789 IRQ Ram Vector
CBINV $0316-0317 790-791 BRK Instr RAM Vector
IOPEN $0318-0319 792-793 Indirects for Code
ICLOSE $031A-031B 794-795
ICHKIN $031C-031D 796-797
ICKOUT $031E-031F 798-799
ICLRCH $0320-0321 800-801
IBASIN $0322-0323 802-803
IBSOUT $0324-Q325 804-805
ISTOP $0326-0327 806-807
IGETIN $0328-0329 808-809
ICLALL $032A-032B 810-811
USRCMD $032C-032D 812-813
ILOAD $032E-032E 814-815
ISAVE $0330-0331 816-817 Savesp
TAPBUF $0333-03F2 819-1010 Cassette tape buffer
WRLEN $03F3-03F4 1011-1012 Length of data to be written to tape
RDCNT $03F5-03F6 1013-1014 Length of data to be read from tape
INPQUE $03F7-0436 1015-1078 RS-232 input queue
ESTARL $0437-0454 1079-1108
ESTAKH $0455-0472 1109-1138
CHRGET $0473-0478 1139-1144
CHRGOT $04?9-0484 1145-1156
QNUM $0485-0493 1157-1171
INDSUB $0494-04A1 1172-1185 Shared ROM fetch sub
ZERO $04A2-04A4 1186-1188 Numeric constant for Basic
INDTXT $04A5-04AF 1189-1199 Txtptr
INDIN1 $04B0-04BA 1200-1210 Index & Index1
INDIN2 $04BB-04C5 1211-1221 Index2
INDST1 $04C6-04D0 1222-1232 Strng1
INDLOW $04D1-04DB 1233-1243 Lowtr
INDFMO $04DC-04E6 1244-1254 Facmo
PUFILL $04E7 1255 Print using fill symbol [space]
PUCOMA $04E8 1256 Print using comma symbol [;]
PUDOT $04E9 1257 Print using D.P. symbol [.]
PUMONY $04EA 1258 Print using monetary symbol [$]
TMPDES $04EB-04EE 1259-1262 Temp for instr
ERRNUM $04EF 1263 Last error number
ERRLIN $04F0-04F1 1264-1265 Line # of last error
TRAPNO $04F2-04F3 1266-1267 Line to go on error
TMPTRP $04F4 1268 Hold trap no. temporarily
ERRTXT $04F5-04E6 1269-1270
OLDSTR $04F7 1271
TMPTXT $04F8-04F9 1272-1273
TMPLIN $04FA-04F8 1274-1275
MTIMLO $04FC-04FD 1276-1277 Table of pending jiffies (2's comp)
MTIMHI $04FE-04FF 1278-1279
USRPOK $0500-0502 1280-1282
KERNDX $0503-0507 1283-1287
DEJAVU $0508 1288 'cold' or 'warm' start status
LAT $0509-0512 1289-1298 Logical file numbers
FAT $0513-051C 1299-1308 Primary device numbers
SAT $051D-0526 1309-1318 Secondary addresses
KEYD $0527-0530 1319-1328 IRQ keyboard buffer
MEMSTR $0531-0532 1329-1330 Start of memory [1000]
MSIZ $0533-0534 1331-1332 Top of memory [FD00]
TIMOUT $0535 1333 IEEE timeout flag
FILEND $0536 1334 File end reached = 1, 0 otherwise
CTALLY $0537 1335 # of chars left in buffer (for R & W)
CBUFVA $0538 1336 # of total valid chars in buffer (R)
TPTR $0539 1337 Ptr to next char in buffer (for R & W)
FLTYPE $053A 1338 Contains type of current cass file
COLOR $053B 1339 Active attribute byte
FLASH $053C 1340 Character flash flag
$053D 1341 FREE
HIBASE $053E 1342 OC Base location of screen (top) [0C]
XMAX $053F 1343
RPTFLG $0540 1344 Key repeat flag
KOUUT $0541 1345
DELAY $0542 1346
SHFLAG $0543 1347 Shift flag byte
LSTSHF $0544 1348 Last shift pattern
KEYLOG $0545-0546 1349-1350 Indirect for keyboard table setup
MODE $0547 1351 shift, C=
AUTODN $0548 1352 Auto scroll down flag (0=on,0<>off)
LINTMP $0549 1353
ROLFLG $054A 1354
FORMAT $054B 1355 Monitor non-zpage storage
MSAL $054C-054E 1356-1358
WRAP $054F 1359
TMPC $0550 1360
DIFF $0551 1361
PCH $0552 1362
PCL $0553 1363
FLGS $0554 1364
ACC $0555 1365
XR $0556 1366
YR $0557 1367
SP $0558 1368
INYL $0559 1369
INVH $055A 1370
CMPFLG $055B 1371 Used by various monitor routines
BAD $055C 1372
KYNDX $055D 1373 Used for programmable keys
KEYIDX $055E 1374
KEYBUF $055F-0566 1375-1382 Table of P.F. lengths
PKY9UF $0567-05E6 1383-1510 P.F. Key storage area
KDATA $05E7 1511 Temp for data write to kennedy
RDYCMD $05E8 1512 Select for kennedy read or write
KDYNUM $05E9 1513 Kennedy's dev #
RDYPRS $05EA 1514 Rennedy present = $ff, else = $00
KDYTYP $05EB 1515 Temp for type of open for kennedy
SAVRAM $05EC-06E8 1516-1771 1 page used by banking routines
PAT $05EC-05EF 1516-1519 Physical Address Table
LNGJMP $05F0-05F1 1520-1521 Long jump address
FETARG $05F2 1522 Long jump accumulator
FETXRG $05F3 1523 Long jump x register
FETSRG $05F4 1524 Long jump status register
AREAS $05F5-065D 1525-1629 RAM areas for banking
ASPECH $065E-06EB 1630-1771 RAM area for speech
STKTOP $06EC-07AF 1772-1967 BASIC run-time stack
WROUT $07B0 1968 Byte to be written on tape
PARITY $07B1 1969 Temp for parity calc
TT1 $07B2 1970 Temp for write-header
TT2 $07B3 1971 Temp for write-header
RDBITS $07B5 1973 Local index for READBYTE routine
ERRSP $07B6 1974 Pointer into the error stack
FPERRS $07B7 1975 Number of first pass errors
DSAMP1 $07B8-07B9 1976-1977 Time constant
DSAMP2 $07BA-07BB 1978-1979 Time constant
ZCELL $07BC-07BD 1980-1981 Time constant
SRECOV $07BE 1982 Stack marker for stopkey recover
DRECOV $07BF 1983 Stack marker for dropkey recover
TRSAVE $07C0-07C3 1984-1987 params passed to RDBLOK
RDETMP $07C4 1988 Temp stat save for RDBLOK
LDRSCN $07C5 1989 # consec shorts to find in leader
CDERRM $07C6 1990 # Errors fatal in RD countdown
VSAVE $07C7 1991 Temp for Verify command
T1PIPE $07C8-a7CB 1992-1995 Pipe temp for T1
ENEXT $07CC 1996 Read error propagate
FOR RS-232
UOUTQ $07CD 1997 User chracter to send
UOUTFG $07CE 1998 0 = empty ; 1 = full
SOUT9 $07CF 1999 System character to send
SOUNFG $07D0 2000 0 = empty ; 1 = full
INOFPT $07D1 2001 Pntr to front of input queue
INQRPT $07D2 2002 Pntr to rear of input queue
INQCNT $07D3 2003 # of chars in input queue
ASTAT $07D4 2004 Temp status for ACIA
AINTMP $07D5 2005 Temp for input routine
ALSTOP $07D6 2006 FLG for local pause
ARSTOP $07D7 2007 FLG for remote pause
APRES $07D8 2008 FLG to indicate presence of ACIA
RLUDES $07D9-07E4 2009-2020 Indirect routine downloaded
SCBOT $07E5 2021 Screen bottom (0...24)
SCTOP $07E6 2022 Screen top
SCLF $07E7 2023 Screen left (0...39)
SCRT $07E8 2024 Screen right
SCRDIS $07E9 2025 Negative = scroll out
INSFLG $07EA 2026 Insert mode: FF = on, 00 = off
LSTCHR $07EB 2027
LOGSCR $07EC 2028
TCOLOR $07ED 2029
BITABL $07EE-07F1 2030-2033
SAREG $07F2 2034 Registers for SYS command
SXREG $07F3 2035
SYREG $07F4 2036
SPREG $07F5 2037
LSTX $07F6 2038 Key scan index
STPDSB $07F7 2039 Flag to disable CTRL-S pause
RAMROM $07F8 2040 MSB for monitor fetches from ROM=0;RAM=1
COLSW $07F9 2041 MSB for color/lim table in RAM=0;ROM=1
FFRMSK $07FA 2042 ROM mask for split screen
VMBMSK $07FB 2043 VM base mask for split screen
LSEM $07FC 2044 Motor lock semaphore for cassette
PALCNT $07FD 2045 PAL tod
TEDATR $0800-0BFF 2048-3071 TED attribute bytes
TEDSCN $0C00-0FFF 3072-4095 TED character pointers
BASBGN $1000- 4096- Start of BASIC text area
BMLUM $1800-1BFF 6144-7167 Luminance for bit map screen
BMCOLR $1C00-1FFF 7168-8191 Color for bit map
Commodore 16 and plus/4 Memory Configuration
$0000 System memory
$0800 Color memory (Text)
$0C00 Video matrix (Text)
$1000 Beginning of BASIC RAM (without graphics)
$1800 Luminance (Graphics)
$1C00 Colour table (Graphics)
$2000 Graphics screen data
$4000 Beginning of BASIC RAM (with graphics)
$8000 ROM BANK LOW (BASIC)
$C000 BASIC expansions
$D000 Character table
$D800 Operating system
$FC00 Routines for switching banks
$FD00 End of BASIC RAM, I/O area
According to the schematics diagram, $FD00-$FF3F contains the following,
regardless of the RAM/ROM banking configuration:
$FD00-FD0F: 6551 ACIA (for the RS232, only on the +4. 4 registers.)
$FD10-FD1F: 6529B (1 register, drives 8 I/O-lines on the +4 user port)
$FD30-FD3F: 6529B (1 register, keyboard scan. The other 8 lines come from TED)
$FF00: TED (registers shown below)
$FF40: ROM
0 Timer 1 low
1 Timer 1 high
2 Timer 2 low
3 Timer 2 high
4 Timer 3 low
5 Timer 3 high
6 Test ECM BMM Blank Rows Y2 Y1 Y0
7 RVS off PAL Freeze MCM Columns X2 X1 X0
8 Keyboard Latch
9 IRQ I-T3 - I-T2 I-T1 I-LP I-RAS -
A - EI-T3 - EI-T2 EI-T1 EI-LP EI-RAS RC8
B RC7 RC6 RC5 RC4 RC3 RC2 RC1 RC0
C - - - - - - C9 CUR8
D CUR7 CUR6 CUR5 CUR4 CUR3 CUR2 CUR1 CUR0
E SND1-7 SND1-6 SND1-5 SND1-4 SND1-3 SND1-2 SND1-1 SND1-0
F SND2-7 SND2-6 SND2-5 SND2-4 SND2-3 SND2-2 SND2-1 SND2-0
10 - - - - - - SND2-9 SND2-8
11 SND-REL Noise V2-SEL V1-SEL VOL3 VOL2 VOL1 VOL0
12 - - BMB2 BMB1 BMB0 R-Bank S1-9 S1-8
13 CB5 CB4 CB3 CB2 CB1 CB0 SCLOCK Status
14 VM4 VM3 VM2 VM1 VM0 - - -
15 - LUM2 LUM1 LUM0 COLOR3 COLOR2 COLOR1 COLOR0
16 - LUM2 LUM1 LUM0 COLOR3 COLOR2 COLOR1 COLOR0
17 - LUM2 LUM1 LUM0 COLOR3 COLOR2 COLOR1 COLOR0
18 - LUM2 LUM1 LUM0 COLOR3 COLOR2 COLOR1 COLOR0
19 - LUM2 LUM1 LUM0 COLOR3 COLOR2 COLOR1 COLOR0
1A - - - - - - BRE9 BRE8
1B BRE7 BRE6 BRE5 BRE4 BRE3 BRE2 BRE1 BRE0
1C - - - - - - - VL8
1D VL7 VL6 VL5 VL4 VL3 VL2 VL1 VL0
1E H8 H7 H6 H5 H4 H3 H2 H1
1F - BL3 BL2 BL1 BL0 VSUB2 VSUB1 VSUB0
3E Write switches on ROM bank
3F Write switches on RAM bank
$FF0E 65294 Voice #1 frequency, bits 0-7
$FF0F 65295 Voice #2 frequency, bits 0-7
$FF10 65296 Voice #2 frequency, bits 8 & 9
(bit 0 is bit 8, bit 1 is bit 9)
$FF11 65297 Bits 0-3 : Volume control
Bit 4 : Voice #1 select
Bit 5 : Voice #2 select
Bit 6 : Voice #2 noise select
Bit 7 : Sound reload
$FF12 65298 Bit 0-1 : Voice #1 frequency, bits 8 & 9
Bit 2 : TED data fetch ROM/RAM select
Bits 0-5 : Bit map base address
$FF13 65299 Bit 0 : Clock status
Bit 1 : Set single clock
Bits 2-7 : Character data base address
$FF14 65309 Bits 3-7 : Video matrix/color memory base address
$FF15 65301 Background color register
Bits 0-3 : Color
Bits 4-6 : Luminance
$FF16 65302 Color register #1
Bits 0-3 : Color
Bits 4-6 : Luminance
$FF17 65303 Color register #2
Bits 0-3 : Color
Bits 4-6 : Luminance
$FF18 65304 Color registes #3
Bits 0-3 : Color
Bits 4-6 : Luminance
$FF19 65305 Color register #4
Bits 0-3 : Color
Bits 4-6 : Luminance
$FF1A 65306 Bit map reload
$FF1B 65307 Bit map reload
$FF1C 65308 Bit 0 : Vertical line bit 8
$FF1D 65309 Bits 0-7 : Vertical line bits 0-7
$FF1E 65310 Horizontal position
$FF1F 65311 Blink, vertical sub address
$FF3E 65342 ROM select
$FF3F 65343 RAM select
BANKING JUMP TABLE
$FCF1 64753 JMP to cartridge IRQ routine
$FCF4 64756 JMP to PHOENIX routine
$FCF7 64759 JMP to LONG FETCH routine
$FCFA 64762 JMP to LONG JUMP routine
$FCFD 64765 JMP to LONG IRQ routine
UNOFFICIAL JUMP TABLE
$FF49 65353 JMP to define function key routine
$FF4C 65356 JMP to PRINT routine
$FF4F 65359 JMP to PRIMM routine
$FF52 65362 JMP to ENTRY routine
$FF80 65408 RELEASE # OF KERNAL (MSB: 0 = NTSC ; 1 = PAL)
KERNAL JUMP TABLE
; NAME ADDRESS DESCRIPTION
; - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
CINT $FF81 65409 Initialize screen editor
IOINIT $FF84 65412 Initialize I/O devices
RAMTAS $FF87 65415 Ram test
RESTOR $FF8A 65418 Restore vectors to initial values
VECTOR $FF8D 65421 Change vectors for user
SETMSG $FF90 65424 Control O.S. messages
SECND $FF93 65427 Send SA after LISTEN
TKSA $FF96 65430 Send SA after TALK
MEMTOP $FF99 65433 Set/Read top of memory
MEMBOT $FF9C 65436 Set/Read bottom of memory
SCNKEY $FF9F 65439 Scan keyboard
SETTMO $FFA2 65442 Set timeout in DMA disk
ACPTR $FFA5 65445 Handshake serial bus or DMA disk byte in
CIoUT $FFA8 65448 Handshake serial bus or DMA disk byte out
UNTLR $FFAB 65451 Send UNTALK out serial bus or DMA disk
UNLSN $FFAE 65454 Send UNLISTEN out serial bus or DMA disk
LISTN $FFB1 65457 Send LISTEN out serial bus or DMA disk
TALK $FFB4 65460 Send TALK out serial bus or DMA disk
READSS $FFB7 65463 Return I/O STATUS byte
SETLFS SEF8A 65466 Set LA, FA, SA
SETNAM $FFBD 65469 Set length and FN address
OPEN $FFC0 65472 Open logical file
CLOSE $FFC3 65475 Close logical file
CHKIN $FFC6 65478 Open channel in
CHOUT $FEC9 65481 open channel out
CLRCH $FECC 65484 Close I/O channels
8ASIN $FFCF 65487 Input from channel
BSOUT $FFD2 65490 output to channel
LOADSP $FFD5 65493 Load from file
SAYESP $FFD8 65496 Save to file
SETTIM $FFDB 65499 Set internal clock
RDTIM $FFDE 65502 Read internal clock
STOP $FFE1 6S50S Scan STOP key
GETIN $FFE4 65508 Get character from queue
CLALL $FFE7 65511 Close all files
UDTIM $FFEA 65514 Increment clock
SCRORG $FFED 65517 Screen org.
PLOT $FFF0 65520 Read/Set X,Y coord of cursor
IOBASE $FFF3 65523 Return location of start of I/O
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