AVR 2313 UART won't work. Please help

Oct 16, 2003 5 Replies

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Daniel Beer 22 years ago

Hello. I just got an STK-500 with an AVR AT90S2313 and i've been trying to write a program to take in a lowercase letter from the UART and display what number letter it is in the alphabet on LEDs. I'm pretty sure my code is ok (see below), Im using a null modem cable to the STK-500 user serial port, and i've wired the RXD and TXD pins on the STK-500 to PD0 and PD1 on the 2313. I hook the other end of the null modem cable to my computer and connect from hyperterminal at 9600 bps 8-n-1. According to the 2313 specs, the BAUD setting (UBBR) for the speed i set the STK-500 to (1.84 Mhz) is 11. However, when i program the chip, nothing happens. I connect from hyperterminal and press letters, but they never affect the LEDs. What am I doing wrong??

Thanks, Daniel

Code: .include "2313def.inc"

.def Temp = R16 .def Input = R17

.org 0x0000 rjmp RESET

.org URXCaddr rjmp SerialInt

RESET: ldi Temp, 255 out DDRB, Temp

ldi Temp, 11 out UBRR, Temp

ldi Temp, (1

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Daniel Beer 22 years ago

SerialInt part should read (wrote SerialInt instead of UDR, see *****'d line)

SerialInt: cli sbis USR, RXC rjmp SerialInt

in Input, UDR ; ***** subi Input, 'a'

com Input out PORTB, Input com Input

sei reti

Fixed that but it still doesnt work. Thanks

what

the

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Don McKenzie 22 years ago

someone may be able to help you on this group Daniel, but I feel in the long run, you will be far better off putting your questions to 4000+ AVR enthusiasts at avrfreaks.net

Give it a try.

Don...

Don McKenzie E-mail: http://www.dontronics.com/e-mail.html Home Page: http://www.dontronics.com USB to RS232 Converter that works http://www.dontronics.com/usb_232.html The World's Largest Range of Atmel/AVR & PICmicro Hardware and Software

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Leon Heller 22 years ago

I've got some code that will get you started here:

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Leon

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Zonn 22 years ago

For one, you don't use a null modem cable with the STK-500, just a simple standard straight through serial cable is all you need...

-Zonn

-------------------------------------------------------- Zonn Moore Zektor, LLC

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Remove the ".AOL" from the email address to reply.

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Jan-Hinnerk Reichert 22 years ago

I vote for bad cabling, wrong oscillator frequency or perhaps wrong serial port in hyperterm.

To rule out cabling (and serial port) use the following program.

rjmp reset

reset: ldi r16,$fe out DDRD,r16

loop: in r16,PIND ; read RxD lsl r16 ; shift RxD to bit1 out PORTD,r16 ; write to TxD jmp loop

Now every character you type in hyperterm should be echoed.

Jan-Hinnerk

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