; B5A7-1.INS for the Apple ][ and CCS 7710 interface for BYE5 - 02/02/87
;
;	       6850 ACIA, no internal baudrate generator
;
;
; This version is for Apple ][ computers, using the Microsoft CP/M card
; and the CCS 7710 serial interface card.
;
;	The 6850 has no baudrate generator.  It relies on the user
;	setting a dip switch to the maximum speed he wants to use.
;	The program then uses the 6850 in the "divide by 16" mode
;	to get that speed.  It can then change to "divide by 64"
;	to get the only other speed available.	This type system
;	normally limits the user to 1200 and 300 baud.	If you
;	set the dip switches for 2400, then you could only get
;	2400 and 600, eliminating both 1200 and 300 baud.  Using
;	either the Apricorn or CCS 7710 board just about precludes
;	the user from wanting to obtain a new modem with 2400 bps.
;	The 6850 uses the last two bits to select the divisor.	01
;	gives "divide by 16" and 10 gives "divide by 64".
;
;-----------------------------------------------------------------------
;
; The CCS 7710 serial card is set up as DCE rather than the more usual
; DTE, and requires a special cable.....the following cable configura-
; ion is necessary to work with this overlay -----
;
;		      MODEM pin       CCS pin
;
;			 2		 3
;			 3		 2
;			 5		 4
;			 8		20
;			 7		 7
;			20		 5
;
; =   =  =   =	 =   =	 =   =	 =   =	 =   =	 =   =	 =   =	 =   =
;
;-----------------------------------------------------------------------
;
; For the Apple //e, a user entered CTL-Q can trash the local display by
; reverting back to 40 column mode.  This is a patch to turn CTL-Q into
; a backspace.
;
; In BYE5 find the label MINP2A:  Just prior to MINP2A should be the
; lines:
;		JNZ	MINP2A
;		MVI	A,08H
;
;
; Add the following code just before JNZ MINP2A
;
;		JZ	CHNGIT
;		CPI	'Q'-'@'
;		JNZ	MINP2A
;	CHNGIT: MVI	A,08H	<< note the added label
;
;
; When using a Softcard CP/M system and the CCS 7710, a warmboot causes
; the serial baud rate port to reset to its default setting.  (Whatever
; the switches are set to on the card.)  The problem is fixed by zeroing
; out the CALL in the warmboot routine that resets the baud rate.
;
; Find the following code in BYE5:
;
;			JMP	VWARMBT
;
; Just before this instruction, add the following code:
;
;			PUSH	PSW	 ;Save AF
;			XRA	A	 ;Make it zero
;			STA	0DAD8H	 ;Patch out the opcode
;			STA	0DAD9H	 ;Patch out the operand byte 1
;			STA	0DADAH	 ;Patch out the operand byte 2
;			POP	PSW	 ;Make it like it was
; Here's the end -->
; For reference -->	JMP	VWARMBT
;
;
; NOTE:  This change may work only with the 60k version version of the
;	 MicroSoft CP/M, their v2.2.3.
;
;
;=  =  =  =  =	=  =  =  =  =  =  =  =	=  =  =  =  =  =  =  =	=  =
;
; 02/02/87  Adapted for the CCS 7710 serial interface card - Irv Hoff
;
;=  =  =  =  =	=  =  =  =  =  =  =  =	=  =  =  =  =  =  =  =	=  =
;
; Equates for Microsoft Softcard CP/M and Super Serial Card
;
SLOT	EQU	2		; Slot of serial interface
SLOTOFF	EQU	16*SLOT		; Serial card slot offset
MAPOFF	EQU	2000H		; Microsoft offset
;
PORT	EQU	0C081H+SLOTOFF+MAPOFF ; Data port
MDCTL1	EQU	PORT-1		; Control port
MDRCV	EQU	1		; Bit to test for receive
MDSND	EQU	2		; Bit to test for send
;......
;
;
;-----------------------------------------------------------------------
;
; Routine to check carrier.  If no carrier, return with zero flag set.
;
MDCARCK:LDA	MDCTL1		; Get status byte
	ANI	4		; Check for DCD
	XRI	4		; Reverse the zero flag (the 6850
	RET			;   has status 0 for DCD true)
;.....
;
;
; This routine will turn off the serial card and hang up the phone.
;
MDINIT:	MVI	A,0D5H		; Turn off DTR
	STA	MDCTL1
	PUSH	B		; Save register
	MVI	B,20		; Delay 2 sec to drop carrier
;
OFFTI:	CALL	DELAY		; 1 sec per loop
	DCR	B
	JNZ	OFFTI		; Keep going until finished
	POP	B		; Restore register
	MVI	A,0B5H		; Turn everything back on, 8 bits, 1 stop
;
	 IF	IMODEM
	CALL	IMINIT
	 ENDIF
;
	RET
;.....
;
;
; Check the status to see if a character is available.	Return with zero
; flag set, if not.  If yes, use 0FFH to clear the flag.
;
MDINST:	LDA	MDCTL1		; Get modem status
	ANI	1		; Is data available?
	RZ			; If no, return
	ORI	0FFH		; Otherwise return true
	RET
;.....
;
;
; See if the output is ready for another character.
;
MDOUTST:LDA	MDCTL1		; Get modem status
	ANI	2		; Mask out junk
	RZ
	ORI	0FFH
	RET
;.....
;
;
; Input a character from the modem port.
;
MDINP:	LDA	PORT		; Get character
	RET
;.....
;
;
; This routine will output a character to the data port.
;
MDOUTP:	STA	PORT		; Send character
	RET
;.....
;
;
; Reinitialize the modem and hang up the phone by dropping DTR and
; leaving it inactive.
;
MDQUIT:	 IF	IMODEM		; If using a smartmodem
	CALL	IMQUIT		; Tell it to shut down
	 ENDIF			; IMODEM
;
;
; Called by the main program after caller types BYE
;
MDSTOP:	MVI	A,0D5H		; Drop DTR, set to 1200 speed
	STA	MDCTL1
	RET
;.....
;
;
; If you do not support a particular baud rate, put it here before
; SETINV:
;
SET2400:
SET4800:
SET9600:
SETINV:	ORI	0FFH
	RET
;.....
;
;
SET300:	MVI	A,16H
	JMP	SETBAUD
;
SET1200:MVI	A,15H
;
SETBAUD:STA	MDCTL1
	XRA	A		; Shows the baud rate was changed ok
	RET
;.....
;
;			    end
;---------------------------------------------------------------------

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