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b3r3-2.ins
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1994-07-13
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3KB
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119 lines
;
; TR1602 I/O and BR19411 baudrate generator
;
; Note: This is an insert not an overlay
;
; Some TRS-80 Model III units may differ from the ones that use this
; insert in which case get the one for the Model IV and try that. The
; status on some of the boards such as the Montezuma Micro CP/M 2.2 are
; inverted and you may or may not have that problem.
;
; = = = = = = = = = = = = = = = = = =
;
; Modem port equates
;
DPORT EQU 0EBH ; Modem port
SPORT EQU DPORT-1 ; Status port
BPORT EQU DPORT-2 ; Baud rate port
RPORT EQU DPORT-3 ; Reset port
;
MDRCV EQU 10000000B ; Data available
MDSND EQU 01000000B ; Xmit buffer empty
MDDCD EQU 00100000B ; Data carrier detect
;
B300 EQU 055H ; 300 baud
B1200 EQU 077H ; 1200 bps
B2400 EQU 0AAH ; 2400 bps
;
;-----------------------------------------------------------------------
;
; See if we still have a carrier - if not, return with the zero flat set
;
MDCARCK:IN RPORT ; Read port
ANI DCD ; Mask carrier detect
RZ
ORI 255
RET
;
; Disconnect and wait for an incoming call
;
MDINIT: MVI A,01 ; Reset UART, enable modem control
OUT RPORT
MVI A,68H ; DTR, RTS off to hang up phone
OUT SPORT
;
PUSH B
MVI B,20 ; 2 seconds to let modem settle down
OFFTI: CALL DELAY
DCR B
JNZ OFFTI
POP B
;
MVI A,6BH ; Turn DTR back on
OUT SPORT
;
IF IMODEM
CALL IMINIT
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 ; Read port
ANI DAV ; Mask crap
RZ ; Nope, nothing there
ORI 255 ; We got something...
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 ; Read port
ANI TBMT ; Mask crap
RZ
ORI 255
RET
;
; Reinitialize the modem and hang up the phone by dropping DTR and
; leaving it inactive.
;
MDQUIT: IF IMODEM
CALL IMQUIT ; Tell smartmodem to shut down
ENDIF ; IMODEM
;
;
; Called by main program after caller has typed BYE
;
MDSTOP: MVI A,68H ; Turn off DTR so that modem will quit
OUT SPORT
RET
;
; The following routine sets the baudrate. BYE3 asks for the maximum
; speed you have available.
;
SET300: MVI A,B300
JMP SETBAUD
;
SET1200:MVI A,B1200
JMP SETBAUD
;
SET2400:MVI A,B2400
;
SETBAUD:OUT BPORT
XRA A
RET
; end
;-----------------------------------------------------------------------