title 'MEX overlay for MEGA SuperComputer SBC' ; ; MXO-MG10.ASM -- MEX Overlay file for the MEGA SuperComputer SBC ; ; Version 1.0: Written 09/04/84 by Ron Fowler ; ; This overlay adapts the MEX modem program to the Mega Computer Co. Single ; Board Computer, using the Zilog SIO or DART. ; ; This overlay is adaptable to any computer using an SIO or DART for ; serial communications, and is especially useful if such adaptations ; are for computer with multiple SIO chips. It's also helpful if ; the target computer uses a CTC for generating the serial clock. ; ; This overlay is capable of setting baud rate and setting port number ; (via the SET command), and setting baud rate from the phone library. ; ; Note: to take advantage of software baud-rate selection, you must strap ; the MEGA baud-rate block (J10) as follows: ; ; CTCI0 - 19200\ For non-MEGA computers, this is a 307KB ; CTCI1 - 19200 > input clock rate (307KB/16=19200) ; CTCI2 - 19200/ ; CTC00 - first SIO clock (RAn, RTAn/RTBn)--\ ; CTC01 - second SIO clock --| ; CTC02 - third SIO clock --| ; |------/ ; | ; These may be to any of the 6 SIO ; clock lines, but MAX of three unless ; you hack in another CTC. You must ; change the values in CTCTBL if you ; don't use CTC port 4 -- SIO on P5 ; CTC port 5 -- SIO on P6 ; CTC port 6 -- SIO on P3 ; ; The SIO channels are numbered as follows: ; ; PORT Connector SIO Chip ; ---- --------- -------- ; 0 P5 U61 ; 1 P6 U61 ; 2 P3 U58 ; 3 P4 U58 (usually, the console) ; 4 P7 U64 ; 5 P8 U64 ; ; The reason for this strange numbering scheme is for compatibility with ; MEGA TurboDOS, where ports 4,5 don't exist (U64 is the network control- ; ler port for TurboDOS, and is not used for RS232 serial communications). ; ; Be aware that, if you're running MEGA TurboDOS, this overlay will dis- ; able the interrupts of any port it's SET to ... you can use the TurboDOS ; version of MEX if this is a problem. You might prefer to use this overlay ; to communicate in terminal mode at the higher baudrates, which is a losing ; situation with the TurboDOS MEX. ; ; Set the following NPORT value to the relative port # (table above) you ; want MEX to use on start up. ; NPORT EQU 1 ; REV EQU 10 ;V 1.0 ; RDA EQU 1 ;mask for recv-data available TBE EQU 4 ;mask for transmit-bufr empty ; ; MEX service processor stuff ; MEX EQU 0D00H ;address of the service processor INMDM EQU 255 ;get char from port to A, CY=no more in 100 ms TIMER EQU 254 ;delay 100ms * reg B TMDINP EQU 253 ;B=# secs to wait for char, cy=no char CHEKCC EQU 252 ;check for ^C from KBD, Z=present SNDRDY EQU 251 ;test for modem-send ready RCVRDY EQU 250 ;test for modem-receive ready SNDCHR EQU 249 ;send a character to the modem (after sndrdy) RCVCHR EQU 248 ;recv a char from modem (after rcvrdy) LOOKUP EQU 247 ;table search: see CMDTBL comments for info PARSFN EQU 246 ;parse filename from input stream BDPARS EQU 245 ;parse baud-rate from input stream SBLANK EQU 244 ;scan input stream to next non-blank EVALA EQU 243 ;evaluate numeric from input stream LKAHED EQU 242 ;get nxt char w/o removing from input GNC EQU 241 ;get char from input, cy=1 if none ILP EQU 240 ;inline print DECOUT EQU 239 ;decimal output PRBAUD EQU 238 ;print baud rate ; PRINT EQU 9 ;BDOS/MEX print-string function call ; BELL EQU 7 ;bell TAB EQU 9 CR EQU 13 ;carriage return LF EQU 10 ;linefeed ESC EQU 1BH ;escape YES EQU 0FFH NO EQU 0 ; ; ORG 100H ; ; Change the clock speed to suit your system ; DS 3 ;(for "JMP START" instruction) DB NO ;yes=PMMI S-100 Modem 103H DB NO ;yes=HAYES Smartmodem, no=non-PMMI 104H DB 'T' ;T=touch, P=pulse (Smartmodem-only) 105H CLOCK: DB 50 ;clock speed in MHz x10, 25.5 MHz max. 106H ;20=2 MHh, 37=3.68 MHz, 40=4 MHz, etc. MSPEED: DB 5 ;0=110 1=300 2=450 3=600 4=710 5=1200 107H ;6=2400 7=4800 8=9600 9=19200 default BYTDLY: DB 5 ;0=0 delay 1=10ms 5=50 ms - 9=90 ms 108H ;default time to send character in ter- ;minal mode file transfer for slow BBS. CRDLY: DB 5 ;0=0 delay 1=100 ms 5=500 ms - 9=900 ms 109H ;default time for extra wait after CRLF ;in terminal mode file transfer COLUMS: DB 5 ;number of DIR columns shown 10AH SETFLG: DB YES ;yes=user-added Setup routine 10BH SCRTST: DB YES ;Cursor control routine 10CH DB YES ;yes=resend a record after any non-ACK 10DH ;no=resend a record after a valid-NAK BAKFLG: DB YES ;yes=change any file same name to .BAK 10EH CRCDFL: DB NO ;yes=default to CRC checking 10FH TOGCRC: DB YES ;yes=allow toggling of CRC to Checksum 110H CVTBS: DB NO ;yes=convert backspace to rub 111H TOGLBK: DB YES ;yes=allow toggling of bksp to rub 112H ADDLF: DB NO ;no=no LF after CR to send file in 113H ;terminal mode (added by remote echo) TOGLF: DB YES ;yes=allow toggling of LF after CR 114H DB YES ;yes=allow transmission of logon 115H ;write logon sequence at location LOGON SAVCCP: DB YES ;yes=do not overwrite CCP 116H DB NO ;yes=local command if EXTCHR precedes 117H ;no=external command if EXTCHR precedes DB YES ;yes=allow toggling of LOCONEXTCHR 118H LSTTST: DB YES ;yes=printer available on printer port 119H XOFTST: DB NO ;yes=checks for XOFF from remote while 11AH ;sending a file in terminal mode XONWT: DB NO ;yes=wait for XON after CR while 11BH ;sending a file in terminal mode TOGXOF: DB YES ;yes=allow toggling of XOFF checking 11CH IGNCTL: DB NO ;yes=CTL-chars above ^M not displayed 11DH EXTRA1: DB 0 ;for future expansion 11EH EXITCHR DB 'E'-40H ;^E = Exit to main menu 11FH BRKCHR: DB '@'-40H ;^@ = Send 300 ms. break tone 120H NOCONN: DB 'N'-40H ;^N = Disconnect from the phone line 121H LOGCHR: DB 'L'-40H ;^L = Send logon 122H LSTCHR: DB 'P'-40H ;^P = Toggle printer 123H UNSAVE: DB 'R'-40H ;^R = Close input text buffer 124H TRNCHR: DB 'T'-40H ;^T = Transmit file to remote 125H SAVCHR: DB 'Y'-40H ;^Y = Open input text buffer 126H EXTCHR: DB '^'-40H ;^^ = Send next character 127H DS 2 ;unused by MEX 128H ; INCTL1: JMP INSP ;go input status port 12AH DS 7 ; OTDATA: JMP OUTDP ;go output data port 134H DS 7 ; INPORT: JMP INDP ;go input data port 13EH DS 7 ; MASKR: ANI RDA ! RET ;bit to test for receive ready 148H TESTR: CPI RDA ! RET ;value of rcv. bit when ready 14BH MASKS: ANI TBE ! RET ;bit to test for send ready 14EH TESTS: CPI TBE ! RET ;value of send bit when ready 151H DS 14 ; 156H ; ; DS 3 ;DIALV: not done here (maybe MXO-SM) 162H DISCV: JMP DISCON ;disconnect GOODBV: JMP GOODBY ; 168H INMODV: JMP NITMOD ;go to user written routine 16BH RET ! NOP ! NOP ;NEWBDV 16EH RET ! NOP ! NOP ;NOPARV 171H RET ! NOP ! NOP ;PARITV 174H SETUPV: JMP SETCMD ; 177H DS 3 ;not used by MEX 17AH VERSNV: JMP SYSVER ; 17DH BREAKV: JMP SBREAK ; 180H ; ; Do not change the following six lines (they provide access to routines ; in MEX that are present to support MDM7 overlays -- they will likely ; be gone by MEX v2.0). ; ILPRTV: DS 3 ; 183H INBUFV DS 3 ; 186H ILCMPV: DS 3 ; 189H INMDMV: DS 3 ; 18CH DS 3 ; 18FH TIMERV DS 3 ; 192H ; ; Routine to clear to end of screen. If using CLREOS and CLRSCRN, set ; SCRTEST to YES at 010AH (above). ; CLREOS: LXI D,EOSMSG ; 195H MVI C,PRINT CALL MEX RET ; CLS: LXI D,CLSMSG ; 19EH MVI C,PRINT CALL MEX RET ; 1A7H ; ; end of fixed area ; SYSVER: MVI C,ILP ;in-line print CALL MEX DB 'MEGA SuperComputer rev ' DB REV/10+'0' DB '.' DB REV MOD 10+'0' DB CR,LF,0 RET ; ; Routine to exit just prior to exit-to-cpm ; GOODBY: RET ;not done here ; ; Send break to remote ; SBREAK: RET ;not yet implemented ; ; Disconnect the modem (not done here, relies on SM overlay) ; DISCON: RET ; ; SET command: select baud rate, port name. Port name may be any of ; ABC, DELTA, USR (names may be changed by altering PNMTBL entries), ; baud rate any of xxxxxxxxxxxxxxxxxxxxx ; Special set-port syntax allows baud rate after port name. Examples: ; ; SET PORT DELTA3 ; SET PORT ABC 1200 ; SET PORT USR 300 ; SET BAUD 9600 ; SETCMD: MVI C,SBLANK ;any arguments? CALL MEX JC TELL ;if not, go display port/baud LXI D,CMDTBL MVI C,LOOKUP CALL MEX ;parse argument PUSH H ;save any parsed argument adrs on stack RNC ;if we have one, return to it POP H ;oops, input not found in table SETERR: MVI C,ILP ;inline print CALL MEX DB CR,LF,'SET command error',CR,LF,0 RET ; ; Argument table ; CMDTBL: DB '?'+80H ;help DW STHELP DB 'BAU','D'+80H ;"set baud" DW STBAUD DB 'POR','T'+80H ;"set port" DW SETPOR DB 0 ;<<=== table terminator ; ; "SET ?" processor ; STHELP: MVI C,ILP ;inline print CALL MEX DB CR,LF,'SET BAUD ' DB CR,LF,'SET PORT ' DB CR,LF DB CR,LF,'Baud rate is one of:' DB CR,LF,' 300 600 1200 4800 9600 19200' DB CR,LF,'Port number is one of:' DB CR,LF,' 0-7 : interfacer 3 or 4 port number' DB CR,LF,' S : System Support I serial port' DB CR,LF,0 RET ; ; "SET BAUD" processor ; STBAUD: MVI C,BDPARS ;function code: parse a baudrate CALL MEX ;let MEX look up code JC SETERR ;jump if invalid code CALL PBAUD ;no, try to set it JC SETERR ;if not one of ours, bomb out BDSHOW: MVI C,ILP ;inline print CALL MEX ;display baud DB 'Baud: ',0 LDA MSPEED ;get current baud rate MVI C,PRBAUD ;let MEX print it CALL MEX RET ; ; SET PORT processor ; SETPOR: MVI C,SBLANK ;scan to argument CALL MEX JC SETERR ;if no arg, bomb out MVI C,GNC ;else consume it CALL MEX SUI '0' ;convert JC SETERR CPI 5+1 JNC SETERR CALL SPA ;set port addresses MVI C,SBLANK ;any thing more? CALL MEX JNC STBAUD ;if so, go parse as baud rate TELL: MVI C,ILP CALL MEX DB CR,LF,'Port: ',0 LDA PORT ADI '0' ;get port # in ASCII STA PORTAS MVI C,ILP CALL MEX PORTAS: DB ' ',0 JMP BDSHOW ; ; Initialize channel ... as distributed, this code simply ; sets the default port, default port addresses, and default ; MSPEED (based on MSPTBL table). You might want to modify ; this do do a full channel initialization, including SIO ; setup and baud rate. If so, delete the commented-out code ; in between NITMOD and SPA, and enter your initial baudrate ; just prior to the call on PBAUD. If you do this, you should ; be aware that whenever you enter MEX, the baudrate will be ; set to this default rate (even if a connection is in prog- ; ress at a different rate). ; NITMOD: MVI A,NPORT ;get initial port number ; ;; De-comment the following for full initialization ;; ;; CALL SPA ;calculate harware port addresses ;; MVI A,?? ;substitute MSPEED baud value for ?? ;; CALL PBAUD ;set rate, init channel ;; RET ;end of init block ; ; Calculate hardware status and data port addresses for ; relative port number passed in A. ; SPA: STA PORT ;save port number MOV E,A ;port # to DE MVI D,0 ;index into table LXI H,PORTBL ;get table of port hardware addresses DAD D DAD D MOV A,M ;fetch status port # STA SPORT ;set it INX H MOV A,M ;fetch data port # STA DPORT LXI H,MSPTBL ;get port's MSPEED value DAD D MOV A,M ;set MSPEED STA MSPEED RET ; ; Port assignment table for each SIO. Each entry ; consists of status-port adrs followed by data- ; port address. ; PORTBL: DB 0EH,0CH ;port 0 (SIO #1, A) DB 0FH,0DH ;port 1 (SIO #1, B) DB 16H,14H ;port 2 (SIO #2, A) DB 17H,15H ;port 3 (SIO #2, B) DB 1AH,18H ;port 4 (SIO #3, A) DB 1BH,19H ;port 5 (SIO #3, B) ; ; This routine sets baud rate passed as MSPEED code in A. ; Returns CY=1 if baud rate not supported (if supported, ; this routine must set the new MSPEED code). ; PBAUD: PUSH H ;don't alter anybody PUSH D PUSH B MOV E,A ;MSPEED code to DE MVI D,0 LDA PORT ;get port # MOV C,A ;to BC MVI B,0 LXI H,BAUDFL ;offset to flags for this port DAD B MOV A,M ;software baudrate supported ORA A ; for this port? STC ;prep carry in case not JZ PBEXIT ;jump if not supported LXI H,MSPTBL ;yes. offset MSPEED for this port DAD B MOV M,E ;store current rate LXI H,MSPEED ;set MSPEED value also MOV M,E LXI H,BAUDTB ;offset into divisor table DAD D ;indexed by SPEED value MOV A,M ;fetch divisor PUSH PSW ;save divisor PUSH B ;save relative port # LDA SPORT ;get status port adrs MOV C,A ;status port adrs to C MVI B,SIOLEN ;b=length of SIO code LXI H,SIONIT ;point to init code DB 0EDH,0B3H ;Z80 OUTIR POP B ;recall relative port # LXI H,CTCTBL ;offset to CTC register, this port DAD B MOV C,M ;PORT # IN C MVI A,45H ;SEND COMMAND CODE DB 0EDH,079H ;Z80 OUTP A instruction POP PSW ;recall divisor DB 0EDH,079H ;Z80 OUTP A instruction ORA A ;return no-errors PBEXIT: POP B POP D POP H RET ; ; table of CTC divisors for each rate ; BAUDTB: DB 175 ;110 (not exact, but close enuf) DB 64 ;300 DB 48 ;450 DB 32 ;600 DB 27 ;710 (not exact) DB 16 ;1200 DB 8 ;2400 DB 4 ;4800 DB 2 ;9600 DB 1 ;19200 ; ; baud rate flags for each SIO port. Set to 0 ; for a port that doesn't support software baudrate ; change, 1 for ports that can. ; BAUDFL: DB 1,1,1,0,0,0 ;6 ports (I have only first 3 connected to CTC) ; ; ; the following table associates each port with a CTC ; hardware address. Valid port addresses must correspond ; with the BAUDFL table above ; CTCTBL: DB 4,5,6,0,0,0 ;only 3 channels available on 1 ctc ; ; The following table holds MSPEED for each port. ; Since it's not possible to tell divisors exist in ; the CTC prior to bringing up MEX, this table is ; set with defaults, and is filled in with actual ; values as each port gets a SET BAUD command. ; MSPTBL: DB 5,5,5,5,5,5 ;speed for each port: 1200 ; ; Init code for an SIO channel ; SIONIT: DB 18H ;reset channel DB 4 ;select write reg 4 DB 44H ;16*clock, 1 stop bit, no parity DB 5 ;select write reg 5 DB 0EAH ;DTR, 8 bits xmit, TX enabl, RTS DB 3 ;select write reg 3 DB 0C1H ;8 bits recv, recv enable SIOLEN EQU $-SIONIT ;length of SIO init code ; ; Port access routines ; ; Input ; INSP: LDA SPORT ;get status-port adrs JMP INP1 INDP: LDA DPORT ;get data-port adrs INP1: STA INP2+1 ;modify the code INP2: IN 0 ;do the input RET ; ; ; output status port ; OUTSP: PUSH PSW ;save the value LDA SPORT ;get port adrs JMP OUTT ;on to common code ; ; output data port ; OUTDP: PUSH PSW ;save the char LDA DPORT ;get data-port adrs OUTT: STA OUT1+1 ;modify the code POP PSW ;recall data byte OUT1: OUT 0 RET ; ; PORT: DS 1 ;put your initial port # here ; DPORT: DS 1 ;data port address SPORT: DS 1 ;status port address ; ; Clear-to-end-of-screen and clear-screen sequences ; EOSMSG: DB ESC,'T','$' CLSMSG: DB 26,'$' ; ; END ;