; B3PH-2.INS - BYE3 insert for Philips "Happy Man" P2000C - 08/01/85
;
;		Zilog Z80-SIO and 8430 CTC timer
;
;	    Note:  This is an insert, not an overlay.
;
; =   =   =   =   =   =   =   =   =   =   =   =   =   =   =   =   =   =
;
DPORT	EQU	28H		; Data port
SPORT	EQU	DPORT+1		; Modem control port
BRPORT	EQU	21H		; Baud rate generator port (CTC)
;
DAV	EQU	00000001B	; Modem receive ready bit
TBMT	EQU	00000100B	; Modem send ready bit
DCD	EQU	00001000B	; Data carrier detect
;
; First byte of CTC Command:
;
BDCMD1	EQU	47H		; Counter mode
;
BD300	EQU	128		; 300 baud
BD1200	EQU	32		; 1200 bps
BD2400	EQU	16		; 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 carrier
	RZ
	ORI	255
	RET
;
; Disconnect and wait for an incoming call
;
MDINIT:	MVI	A,0		; Setup to write register 0
	OUT	SPORT
	MVI	A,18H		; Reset channel
	OUT	SPORT
	MVI	A,4		; Setup to write register 4
	OUT	SPORT
	MVI	A,44H		; Set 16x, 1 stop bit, no parity
	OUT	SPORT
	MVI	A,3		; Setup to write register 3
	OUT	SPORT
	MVI	A,0C1H		; 8 bits, Rx enable
	OUT	SPORT
	MVI	A,5		; Setup to write register 5
	OUT	SPORT
	MVI	A,68H		; DTR off
	OUT	SPORT
;
	PUSH	B		; Save in case it's being used elsewhere
	MVI	B,20		; 2 second delay to drop any carrier
OFFTI:	CALL	DELAY		; 1 second delay
	DCR	B
	JNZ	OFFTI		; Keep looping until finished
	POP	B		; Restore 'BC'
;
	MVI	A,5		; Setup to write register 5
	OUT	SPORT
	MVI	A,0E8H		; Turn DTR back on
	OUT	SPORT
;
	 IF	IMODEM		; If using an intellegent 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.  I fyes, 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
	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		; Get status
	ANI	TBMT		; Ready for a character?
	RZ
	ORI	255
	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		; Turn off DTR until next time
	OUT	SPORT
	RET
;
; The following routine sets the baudrate.  BYE3 asks for the maximum
; speed you have available.
;
SET300:	MVI	B,BD300		; Set for 300 baud
	JMP	SETBAUD
;
SET1200:MVI	B,BD1200	; Set for 1200 bps
	JMP	SETBAUD
;
SET2400:MVI	B,BD2400	; Set for 2400 bps
;
SETBAUD:MVI	A,BDCMD1	; Get CTC command word
	OUT	BRPORT		; Send first byte of command
	MOV	A,B		; Restore the baudrate
	OUT	BRPORT		; Send rate
	XRA	A		; Say rate is ok
	RET
;			       end
;-----------------------------------------------------------------------