; B5DP-1.INS - BYE5 insert for Datapoint 1560 - 07/17/85
;
; 8251A and 8430 CTC timer 3.6864 MHz
;
; Note: This is an insert, not an overlay
;
; = = = = = = = = = = = = = = = = = =
;
; 07/17/85 Written to work with BYE5 - Irv Hoff
;
; = = = = = = = = = = = = = = = = = =
;
;
; The following define the port addresses to use
;
PORT EQU 28H ; Modem base port
MDCTL1 EQU PORT+1 ; Modem control port
RCVPORT EQU 20H ; Receive speed CTC port
XMTPORT EQU 1AH ; Transmit speed CTC port
;
MDRCV EQU 2 ; Modem receive ready bit
MDSND EQU 1 ; Modem send ready bit
RESET EQU 38H ; Framing, overrun and parity errors
;
MDMODE EQU 82H ; Insures 8251 is out of mode, DTR high
MDRSET EQU 42H ; Resets USART for additional commands
MDSET1 EQU 4EH ; 1 stop bit, no parity, 8 bits, x16
MDSET2 EQU 0CEH ; 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 MDCTL1 ; Get status
ANI 80H ; Check DSR for carrier from modem
RET
;.....
;
;
; Disconnect and wait for an incoming call.
;
MDINIT: MVI A,10H ; Clear DTR
OUT MDCTL1 ; 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 MDCTL1
XTHL ; Delay a little
XTHL ; Delay a little
MVI A,MDRSET ; Reset the 8251A for new command
OUT MDCTL1
XTHL
XTHL
MVI A,MDSET1 ; Set stop pulse, no parity 8 bits, x16
OUT MDCTL1
XTHL
XTHL
MVI A,17H ; Reset error flags, RCV, DTR, TX ready
OUT MDCTL1
XTHL
XTHL
;
IF IMODEM
CALL IMINIT ; Initialize smartmodem
ENDIF ; IMODEM
;
RET
;.....
;
;
; Input a character from the modem port
;
MDINP: IN PORT ; 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 MDCTL1 ; Get status
ANI MDRCV ; Got a character?
RZ ; Return if none
IN MDCTL1 ; Get status again
ANI RESET ; Check for framing and overrun
JZ MDINST1 ; No errors
MVI A,17H ; Reset error flags
OUT MDCTL1
XRA A ; Return false
RET
;...
;
;
MDINST1:ORI 0FFH ; We have a character
RET
;.....
;
;
; Send a character t the modem
;
MDOUTP: OUT PORT ; Send it
RET
;.....
;
;
; See if the output is ready for another character
;
MDOUTST:IN MDCTL1
ANI MDSND
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 MDCTL1 ; so will not auto-answer at any time
RET
;.....
;
;
; The following routine sets the baudrte. BYE5 asks for the maximum
; speed you have available.
;
SETINV: MVI A,0FFH
ORA A ; Make sure the Zero flag isn't set
RET
;.....
;
;
SET300: MVI B,BD300 ; Load 300 baud
JMP SETSPD
;
SET1200:MVI B,BD1200 ; Poke in 1200 bps
JMP SETSPD
;
SET2400:MVI B,BD2400 ; Load 1200 bps
;
SETSPD: MVI A,47H ; First byte of baudrate
OUT RCVPORT
OUT XMTPORT
MOV A,B ; Second byte of baudrate
OUT RCVPORT
OUT XMTPORT
XRA A ; Say it is ok
RET
;.....
;
; end
;-----------------------------------------------------------------------
