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-
- ; B3DP-2.INS - BYE3 insert for Datapoint 1560 - 07/30/85
- ;
- ; 8251A and 8430 CTC timer 3.6864 MHz
- ;
- ; Note: This is an insert, not an overlay
- ;
- ; = = = = = = = = = = = = = = = = = =
- ;
- ; 07/30/85 Restored to original format - pst
- ; 11/25/84 Created - Irv Hoff
- ;
- ; = = = = = = = = = = = = = = = = = =
- ;
- ; The following define the port addresses to use
- ;
- DPORT EQU 28H ; Modem base port
- SPORT EQU DPORT+1 ; Modem control port
- RBPORT EQU 20H ; Receive speed CTC port
- TBPORT EQU 1AH ; Transmit speed CTC port
- ;
- DAV EQU 00000010B ; Data available
- TBMT EQU 00000001B ; Transmit buffer empty
- DCD EQU 10000000B ; Data carrier detect
- ;
- RESET EQU 00111000H ; Framing, overrun and parity errors
- ;
- MDMODE EQU 10000010H ; Insures 8251 is out of mode, DTR high
- MDRSET EQU 01000010H ; Resets USART for additional commands
- MDSET1 EQU 01001110H ; 1 stop bit, no parity, 8 bits, x16
- MDSET2 EQU 11001110H ; 2 stop bits, no parity, 8 bits, x16
- ;
- ; The following are CTC timer baud rates divisors.
- ;
- BD300 EQU 32 ; 9600/300 = 300 bps
- BD1200 EQU 8 ; 9600/1200 = 1200 bps
- BD2400 EQU 4 ; 9600/2400 = 2400 bps
- ;
- ;-----------------------------------------------------------------------
- ;
- ; See if we still have a carrier - if not, return with the zero flag set
- ;
- MDCARCK:IN SPORT ; Get status
- ANI DCD ; Check DSR for carrier from modem
- RZ
- ORI 255
- RET
- ;
- ; Disconnect and wait for an incoming call.
- ;
- MDINIT: MVI A,10H ; Clear DTR
- OUT SPORT ; Causing hangup
- ;
- PUSH B ; Preserve in case we need it
- MVI B,20 ; 2 seconds to drop DTR
- OFFTI: CALL DELAY ; 0.1 second delay
- DCR B
- JNZ OFFTI ; Keep waiting until carrier drops
- POP B ; Restore BC
- ;
- MVI A,MDMODE ; Insure 8251 is out of mode
- OUT SPORT
- XTHL ; Delay a little
- XTHL ; Delay a little
- MVI A,MDRSET ; Reset the 8251A for new command
- OUT SPORT
- XTHL
- XTHL
- MVI A,MDSET1 ; Set stop pulse, no parity 8 bits, x16
- OUT SPORT
- XTHL
- XTHL
- MVI A,17H ; Reset error flags, RCV, DTR, TX ready
- OUT SPORT
- XTHL
- XTHL
- ;
- IF IMODEM
- CALL IMINIT ; Initialize smartmodem
- ENDIF ; IMODEM
- ;
- RET
- ;
- ; Input a character from the modem port
- ;
- MDINP: IN DPORT ; Get character
- RET
- ;
- ; Check the status to see if a character is available. if not, return
- ; with the zero flag set. If yes, use 0FFH to clear the flag.
- ;
- MDINST: IN SPORT ; Get status
- ANI DAV ; Got a character?
- RZ ; Return if none
- IN SPORT ; Get status again
- ANI RESET ; Check for framing and overrun
- JZ MDINST1 ; No errors
- MVI A,17H ; Reset error flags
- OUT SPORT
- XRA A ; Return false
- RET
- ;
- MDINST1:ORI 255 ; We have a character
- RET
- ;
- ; Send a character to the modem
- ;
- MDOUTP: OUT DPORT ; Send it
- RET
- ;
- ; See if the output is ready for another character
- ;
- MDOUTST:IN SPORT
- ANI TBMT
- RET
- ;
- ; Renitialize the modem and hang up the phone by dropping DTR and
- ; leaving it inactive.
- ;
- MDQUIT: IF IMODEM
- CALL IMQUIT
- ENDIF ; IMODEM
- ;
- ; Called by the main program after caller types BYE
- ;
- MDSTOP: MVI A,10H ; DTR low hangs up phone, keep DTR low
- OUT SPORT ; so will not auto-answer at any time
- RET
- ;
- ; The following routine sets the baudrte. BYE3 asks for the maximum
- ; speed you have available.
- ;
- SET300: MVI B,BD300 ; Load 300 baud
- JMP SETSPD
- ;
- SET1200:MVI B,BD1200 ; Load 1200 baud
- JMP SETSPD
- ;
- SET2400:MVI B,BD2400 ; Load 2400 baud
- ;
- SETSPD: MVI A,47H ; First byte of baudrate
- OUT RBPORT
- OUT TBPORT
- MOV A,B ; Second byte of baudrate
- OUT RBPORT
- OUT TBPORT
- XRA A ; Say it is ok
- RET
- ; end
- ;-----------------------------------------------------------------------