; B5C8-1E.INS - BYE5 insert for Commodore C128, external modem - 7/21/86
;
;  Modifications by David Giunti,  July 20, 1986
;	change MDCARCK to correct the actual PORT check
;	  Note all the I/O in the C=128 is located in Bank 0, and can 
;	  be read and written useing the Z80's IN and OUT with 16bit
;	  pointers. 
;	  
;	Added a CMA in the MDOUTST
;
;	I'm still not sure if MHZ should be 1 rather than 2, as this
;		.INS could not have worked without MDCARCK
;  July 21.  This .INS will work correctly with MHZ set to 2.  If 
;  you have an 80col monitor use Von Ertwine's CONFIG to set 40COL=OFF
;  as this gives a 10%+ system speed-up.  Get a copy of CCP+.LBR and use it.
;  July 26.   The TSTBAUD: routine requires that the Zero flag be set to 
;  know that the  baudrate was correctly set, and MDIN2: returns it set 
;  so rather than just comment out the code in the main BYE509 I'll add
;  some ugly code to set the Zero Flag manually. 
;
; .INS is now very ready for final test
;      Dave Giunti  
;======================Original Header============12/12/85===========
;	IMPORTANT:  When going through the options for
;		    BYE5, be sure to set:
;
;				MHZ  EQU  1
;
;		    regardless what you think it should
;		    be set for.  The modem routines built
;		    into the Commodore IOS use "bit-bang-
;		    ing" interrupt control and this value
;		    should be used.  (All this does is
;		    control the number of loops used for
;		    timing purposes.)
;
; =   =   =   =   =   =   =   =   =   =   =   =   =   =   =   =   =   =
;
; 12/12/85  Written to work with BYE5		- Irv Hoff
; 07/21/86  modified version for BYE509 from work done by
;           Irv Hoff and George Peace                    - David Giunti
; =   =   =   =   =   =   =   =   =   =   =   =   =   =   =   =   =   =
;
; C128 data
;
PORT	EQU	6
MEMRY	EQU	0FD4EH
MDCTL1	EQU	MEMRY+1
SNDDAT	EQU	MEMRY+2
RCVDAT	EQU	MEMRY+3
MDDCD	EQU	10H		; Bit 4 to test for DCD
MDRCV	EQU	01H		; Bit 0 to test for receive ready
MDSND	EQU	80H		; Bit 7 to test for send
;
CBNK	EQU	0FD1DH		; Address of the current bank byte
;
;
; Table of baudrate parameters
;
BD300	EQU	6		; Divisor for 300 baud
BD1200	EQU	8		; Divisor for 1200 bps (The Commodore
				;   C128 does not support faster speeds
				;   in the CP/M-128 mode)
;
;-----------------------------------------------------------------------
;
; See if we still have a carrier - if not, return with the zero flag set
;
MDCARCK:
;	LDA	0DD01H		; Get status
;       this should be an IN like in MDINIT below to work correctly -dag
	PUSH	B		; save reg
	LXI	B,0DD01H	; point at data port B
	DB	0EDH,78H	; Input to A, pointed by BC
	CMA			; Invert the value for active low
	ANI	MDDCD		; Check DCD for carrier from modem
	POP	B		; restore B reg
	RET
;.....
;
;
; Disconnect and wait for an incoming call.
;
MDINIT:	LXI	B,0DD01H	; Dataport B
	DB	0EDH,78H	; Input A (Z80 instruction)
	ANI	0F9H
	DB	0EDH,79H	; Output the new value, to disconnect
	MVI	B,20		; 2 seconds to drop DTR

MDIN1:	CALL	DELAY		; 0.1 second delay
	DCR	B
	JNZ	MDIN1		; Keep waiting until carrier drops
	LXI	B,0DD01H	; Reset back to normal
	DB	0EDH,78H
	ORI	6
	DB	0EDH,79H
	MVI	A,1		; Set to 8 bits, no parity
	STA	MEMRY		; Configure byte in BIOS
	MVI	B,BD300		; Initialize to 300 baud
;.....
;
;
; Initialize the port, baudrate is now in the B-reg. find where it goes
; and put it there.
;
MDIN2:	PUSH	B		; Temporarily store the baudrate value
	LHLD	0000H+1		; Get BIOS address
	LXI	D,57		; CP/M JMP device table
	DAD	D		; Index into BIOS
	CALL	MDIN3		; Jumps to address now in HL
				; returns with HL=char device tbl start
	LXI	D,PORT*8+7	; Offset to RS232 baud rate
	DAD	D		; Point to RS232 baud rate byte
				;   Byte now in HL
	POP	B		; Get the baudrate value back
	MOV	M,B		; Store the requested baud rate
;
;
; Have now stored desired baudrate, find the address in BIOS where the
; port will be initialized, put the correct port into the 'C' register
; and then initialize that port to baud rate just set, finished.
;
	LHLD	0000H+1		; Get BIOS address
	LXI	D,60		; CP/M init address
	DAD	D		; Index into BIOS
	MVI	C,PORT		; Tell it what port to initialize
	CALL	MDIN3
;
	xra	a		; clears all bits in Acum, sets Zero flag -dag
;
;
; Jumps to HL address, performs that routine, then returns here
;
	 IF	IMODEM
	CALL	IMINIT		; Initialize smartmodem
	 ENDIF			; IMODEM
;
	RET
;...
;
;
MDIN3:	PCHL			; Jump to that routine then return
;.....
;
;
; Input a character from the modem port
;
MDINP:	LDA	RCVDAT		; Get character
;
;
; We found there was a character, got it, but have to manually reset the
; flag to zero saying we did get the character.
;
	PUSH	H		; Save the current address just in case
	LXI	H,MDCTL1	; Address of status byte
	DB	0CBH,86H	; Reset the 0 bit of the HL status byte
	POP	H		; Restore the original address
	RET			; Return with the character
;.....
;
;
; 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.
;
;  note that CMA is not required here because of the logical construction
MDINST:	LDA	MDCTL1		; Get status
	ANI	MDRCV
	RZ			; No character, return
;...
;
;
MDINST1:ORI	0FFH		; We have a character, clear the flag
	RET
;.....
;
;
; Send a character to the modem
;
MDOUTP:	STA	SNDDAT		; Output the character
;
;
; Output character has been stored in the BIOS memory location, now set
; the flag showing there is a charcter ready.
;
	PUSH	H		; Save any current address, if needed
	LXI	H,MDCTL1	; Address of the status byte
	DB	0CBH,0FEH	; Set bit 7 of the HL status byte
	POP	H		; Get the original address back
	RET			; All done
;.....
;
;
; See if the output is ready for another character
;
MDOUTST:LDA	MDCTL1		; Get the status bit
	cma			; invert bits for check -dag
	ANI	MDSND		; Check send ready bit
	RET			; If pin is high, not ready
;.....
;
;
; 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	B,BD300		; Initialize to 300 baud
	CALL	MDIN2		; Set to 300 baud to speed up C128
	LXI	B,0DD01H	; Dataport B
	DB	0EDH,78H	; Input A (Z80 instruction)
	ANI	0F9H		; Keep DTR set low permanently
	DB	0EDH,79H	; Output the new value, to disconnect
	RET
;.....
;
;
; The following routine sets the baudrte.  BYE5 asks for the maximum
; speed you have available.
;
SET2400	EQU	0
;
SETINV:	MVI	A,0FFH
	ORA	A		; Make sure the Zero flag isn't set
	RET
;.....
;
;
SET300:	MVI	B,BD300		; Get 300 baud parameters in 'HL'
	JMP	MDIN2
;

SET1200:MVI	B,BD1200
	JMP	MDIN2
;.....
;
;
;-----------------------------------------------------------------------
;			CP/M v3.0 routines
;
; Perform system or hardware dependent PRE-processing.	The following
; code will be executed by the PATCH subroutine before the BIOS jump
; table is overwritten.
;
MDPREP:	RET
;.....
;
;
; Perform system or hardware dependent POST-processing.
; The following code will be executed by the EXCPM routine before re-
; turning control to CP/M Plus when the BYE5 program is terminated.
;
MDPOSP:	RET
;.....
;
;			       end
;-----------------------------------------------------------------------
minated.
;
MDPOSP:	RET
;.....
;
;			       end
;--------------------------------------
.
