;======================================================================
; UART and Baud Rate initialization code (9_Nov_84)
;==================================================
;
;	Copyright 1984
;	Morrow Designs, Inc.
;	San Leandro, Ca.
;	Written by David Block and Jim Kearney (September 1983)
;
;----------------------------------------------------------------------
; Index (9_Nov_84)
;-----------------
;
;	INIUART	Initialize the Uart Main Line
;	SETBAUD	Determine the Baud Rate
;	SETUART	Set the Uart's Baud Rate
;	INIT8	Set the Uart's Reciever/Transmitter Format
	PAGE

;----------------------------------------------------------------------
; Uart Initialization
;--------------------
;
INIUART:JSR	SETBAUD		;determine baud rate selection bits
	JSR	SETUART		;setup UART for proper BAUD rate, etc
	JSR	INIT8		;set status of bit 8 parity, or mark, or space
	RTS

;----------------------------------------------------------------------
; Determine the Baud Rate Settings
;---------------------------------
;
SETBAUD:LDA	BDREG		;get current contents of baud register
	AND	#$F9		;Clear BD0 and BD1
	STA	BDREG
	LDA	DIP1		;get dipsw value
	AND	#$03		;get baud rate selection bits
	ASL	A		;align with BDREG
	ORA	BDREG		;set/clr baud bits
	STA	BDREG		;Save it
	STA	BAUD		;and set baud bits
	RTS
	PAGE

;----------------------------------------------------------------------
; Set the Uart Baud Rate
;-----------------------
;
SETUART:LDX	#$80		;after setting baud rate, wait to settle
SULP1:	DEX
	BNE	SULP1

	LDA	#$80		;reset USART
	STA	S1STAT
	TAX
	TAX			;WAIT
	STA	S1STAT
	LDA	#$40
	STA	S1STAT		;Put USART in command mode
	LDA	DIP1		;get dip switch settings
	AND	#%00001100	;get the parity select bits
	ASL	A
	ASL	A		;align them for USART Mode byte
	STA	TEMP		;put it aside
	LDA	DIP1		;get dip switch 
	AND	#%00000010	;determine if it needs /16 or /64
	LSR	A		;move the determining bit over
	ORA	TEMP		;get parity select bits back
	ORA	#%01001110	;OR in USART MODE boiler plate (8-data, 1-stop)
	STA	S1STAT		;set USART Mode
	LDA	#%00110111	;get enable byte for USART
	STA	S1STAT		;Enable USART
	STA	UARTCMD		;save it in command instr. register
	LDA	S1DATA		;Flush one character
	RTS

;----------------------------------------------------------------------
; Set Transmission/Reception Format
;----------------------------------
;
INIT8:	LDA	DIP1		;get dip setings
	LSR	A		;get parity on/off status
	LSR	A
	TAX
	AND	#%00000001
	STA	PARSTAT		;save it in parity status
	TXA
	LSR	A
	AND	#%00000001	;get whether mark or space/ odd/even
	STA	BIT8
	RTS
	PAGE

	END