;
;==================================================================================================
; eZ80 UART DRIVER (SERIAL PORT)
;==================================================================================================
;

UART0_LSR	.EQU	$C5
UART0_THR	.EQU	$C0
UART0_RBR	.EQU	$C0

LSR_THRE	.EQU	$20
LSR_DR		.EQU	$01

#DEFINE IN0_A(p)	.DB	$ED,$38,p
#DEFINE IN0_B(p)	.DB	$ED,$00,p
#DEFINE IN0_C(p)	.DB	$ED,$08,p
#DEFINE IN0_D(p)	.DB	$ED,$10,p
#DEFINE IN0_E(p)	.DB	$ED,$18,p
#DEFINE IN0_H(p)	.DB	$ED,$20,p
#DEFINE IN0_L(p)	.DB	$ED,$28,p

#DEFINE OUT0_A(p)	.DB	$ED,$39,p
#DEFINE OUT0_B(p)	.DB	$ED,$01,p
#DEFINE OUT0_C(p)	.DB	$ED,$09,p
#DEFINE OUT0_D(p)	.DB	$ED,$11,p
#DEFINE OUT0_E(p)	.DB	$ED,$19,p
#DEFINE OUT0_H(p)	.DB	$ED,$21,p
#DEFINE OUT0_L(p)	.DB	$ED,$29,p

EZUART_PREINIT:
	LD	BC, EZUART_FNTBL
	LD	DE, EZUART_CFG		
	CALL	CIO_ADDENT
	LD	(EZUART_ID), A

	XOR	A
	RET

EZUART_INIT:
	XOR	A
	RET


; RETRIEVE THE NEXT CHARACTER FROM THE UART AND RETURN IN E
EZUART_IN:
	IN0_A	(UART0_LSR)		; CHECK FOR RX READY
	AND	LSR_DR
	JR	Z, EZUART_IN
	
	IN0_E	(UART0_RBR)		; GET THE CHAR

	XOR	A			; SIGNAL SUCCESS
	RET
	
; OUT CHAR IN E
EZUART_OUT:
	IN0_A	(UART0_LSR)		; WAIT FOR TX READY
	AND	LSR_THRE
	JR	Z, EZUART_OUT
     
	OUT0_E	(UART0_THR)		; SEND THE CHAR

	XOR	A			; SIGNAL SUCCESS
	RET

EZUART_IST:
	IN0_A	(UART0_LSR)		; CHECK FOR RX READY
	AND	LSR_DR
	RET

EZUART_OST:
	IN0_A	(UART0_LSR)		; WAIT FOR TX READY
	AND	LSR_THRE
	RET	Z
	LD	A, 1
	RET

EZUART_INITDEV:
EZUART_QUERY:
	LD	A, 0			; NOT IMPLEMENTED ERROR
	RET

EZUART_DEVICE:
	LD	D, CIODEV_EZ80UART	; D := DEVICE TYPE
	LD	E, (IY)			; E := PHYSICAL UNIT
	LD	C, 0			; C := DEVICE TYPE, 0x00 IS RS-232
	LD	HL, 0			; H := MODE, L := BASE I/O ADDRESS
	
	XOR	A			; SIGNAL SUCCESS
	RET

EZUART_CFG:
EZUART_ID:	.DB	0

	
EZUART_FNTBL:
	.DW	EZUART_IN
	.DW	EZUART_OUT
	.DW	EZUART_IST
	.DW	EZUART_OST
	.DW	EZUART_INITDEV
	.DW	EZUART_QUERY
	.DW	EZUART_DEVICE
#IF (($ - EZUART_FNTBL) != (CIO_FNCNT * 2))
	.ECHO	"*** INVALID EZUART FUNCTION TABLE ***\n"