; This is a simple demonstration of sending characters via the 2313 UART.

; Here we are using a clock speed of 3.6864 MHz.  The UBRR setting depends

; on the clock speed and baud rate.



; The program scrolls a continuous stream of characters when connected a terminal

; by sending all the printable characters from 32 to 123 decimal or whatever

; values are stored initially in char and in upper.  This program was intended

; mainly to show the performance of serial I/O on the AVR.  Very impressive

; throughput is possible.  Without the delay it can overrun a PC serial port.

; The delay just makes the scrolling go slower so you can read it.  Can do 115K

; baud with just a 3.6864 MHz clock on the AVR!

;

; Written by Brian Hammill 5/98

; This code is given as is and placed in the public domain.  No warranty of any kind

; is implied or given.  Questions or comments about the code may be directed

; to me via Email: hammill@email.exide.com.  I don't promise to support this

; code, but will offer suggestions as my schedule allows.  Good luck. 



.include "2313def.inc"





.def	Temp	=r16		;temporary register

.def	Delay	=r17

.def	Delay2	=r18

.def	upper	=r19

.def	char	=r20

;***** Initialization

;

	



RESET:

	ldi	Temp, $18

	out	UCR, Temp

	ldi	char, 32	; start with '0'

	ldi	upper, 123

	; determine the baud rate from the clock freq. using the formula:

	; BAUD = Fck/16*(UBRR + 1)

	; 3.6864 (or multiples of) give nice baud rates with no errors.

	;ldi	Temp, 95	; Baud Rate = 2400 at 3.6864 MHz

	;ldi	Temp, 1		; Baud Rate = 115200

	ldi	Temp, 190	; Baud Rate = 1200

	out 	UBRR, Temp

LOOP1:	

	out	UDR, char	; output char to UART Data Reg

	inc	char		; next char



DLY:	dec	Delay

	dec	Delay

	inc	Delay

	brne	DLY

	dec	Delay2

	brne	DLY

	

	

	;inc 	char

	

	

	cp	upper, char

	brne	LOOP1

	ldi	char, 32

	rjmp	LOOP1