; B3EP-1.INS - BYE3 insert for Epson QX-10 computers - 07/30/85
;
; Z80 SIO and 8253 CTC timer
;
; Note: This is an insert, not an overlay.
;
;
; = = = = = = = = = = = = = = = = = =
;
; 07/30/85 - Restored original format of overlay - pst
; 12/15/83 - Created - Albert Doolittle
;
; = = = = = = = = = = = = = = = = = =
;
;
DPORT EQU 11H ; Data port
SPORT EQU PORT+2 ; Status/Control port
CTC0 EQU 06H ; CTC baudrate port
CTC1 EQU CTC0+1 ; Vector port
;
DAV EQU 00000001B ; Data available
TBMT EQU 00000100B ; Transmitt buffer empty
DCD EQU 00001000B ; Data carrier detect
;
; Now comes the time to decide how we set the baud rate. Set it prop-
; erly for your particular CTC configuration
;
BDVECT EQU 0B6H ; QX-10 Vector word
;
BD300 EQU 01A0H ; 300 baud
BD1200 EQU 0068H ; 1200 bps
BD2400 EQU 0034H ; 2400 bps
;
;-----------------------------------------------------------------------
;
; See if we still have a carrier - if not, return with the zero flag set
;
MDCARCK:MVI A,10H ; Reset status
OUT SPORT
IN SPORT ; Get status
ANI DCD ; Check for data carrier
RZ
ORI 255
RET
;
; Disconnect and wait for an incoming call
;
MDINIT: MVI A,0 ; Select Register
OUT SPORT
MVI A,18H ; Reset channel
OUT SPORT
MVI A,4 ; Setup to write register 4
OUT SPORT
MVI A,44H ; 1 stop, no parity, 8 bits
OUT SPORT
MVI A,1 ; Setup to write register 1
OUT SPORT
MVI A,68H ; DTR off
OUT SPORT
MVI A,5 ; Setup to write register 5
OUT SPORT
MVI A,0 ; Clear DTR
OUT SPORT ; Causing Hang-Up
IN DPORT ; Clear out garbage
IN DPORT ; Make sure we're clear
PUSH B ; In case it's being used elsewhere
MVI B,20 ; 2 seconds delay to drop any carrier
;
OFFTI: CALL DELAY ; 0.1 second delay
DCR B
JNZ OFFTI ; Keep looping until finished
POP B ; Restore BC
MVI A,3 ; Setup to write register 3
OUT SPORT
MVI A,0C1H ; Initialize receive register
OUT SPORT
MVI A,5 ; Setup to write register 5
OUT SPORT
MVI A,0EAH ; DTR high lets the modem answer phone
OUT SPORT
;
IF IMODEM ; If using an intelligent modem
CALL IMINIT ; Go initialize it now
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 ; Check the receive ready bit
RZ ; Return if none
ORI 255 ; Otherwise, set the proper flag
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 ; Check the transmit ready bit
RET
;
; Reinitialize 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,5 ; Setup to write register 5
OUT SPORT
MVI A,68H ; Clear DTR
OUT SPORT ; Causing Hang-Up
IN DPORT ; Clear out garbage
IN DPORT ; Make sure we're clear
RET ; Not used
;
; The following reoutine sets the baudrate. BYE3 asks for the maximum
; speed you have available.
;
SET300: LXI H,BD300
JMP LOADBD
;
SET1200:LXI H,BD1200
JMP LOADBD
;
SET2400:LXI H,BD2400
;
LOADBD: MVI A,BDVECT ; Get vector address
OUT CTC1 ; Send to CTC
MOV A,L ; MSP of baudrate
OUT CTC0
MOV A,H
OUT CTC0
RET
;
; end
;-----------------------------------------------------------------------
