AT89C51ED2 UART not work?

check the connections to your MAX232(equivalent) and the signals there with a scope.

Also verify the baudrate both ways.

Erik

I am sure the connections is right.
because it is a development kit board.
The board use the same port which is RS232 DB9 connector to download the hex file(use FLIP).

The C source file was downloaded from ATMEL.
I don't modify it.
The SPI example(ATMEL) is work, and the UART example cant...>_<

I had search the internet, someone says that
maybe the UART use 9bit or else.
It makes the PC COM1 can't read correct.

PS. I dont have oscilloscope, I just a student. >_<

what baudrate, how is it set?

Erik

you can find the source code in following link
http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3420

I use C51 UART Mode1 Timer1 (24 KB, updated 06/04)
9600bps
Regard.

I use C51 UART Mode1 Timer1 (24 KB, updated 06/04) 9600bps
what are the SFRs (SCON, TCON, TMOD, TH1, TL1, IE set to)

Erik

hi erik
the same with the source code.
SCON = 0x50; /* uart in mode 1 (8 bit), REN=1 */
TMOD = TMOD | 0x20 ; /* Timer 1 in mode 2 */
TH1 = 0xFD; /* 9600 Bds at 11.059MHz */
TL1 = 0xFD; /* 9600 Bds at 11.059MHz */
ES = 1; /* Enable serial interrupt */
EA = 1; /* Enable global interrupt */
TR1 = 1; /* Timer 1 run */

I didn't modify it.

Regard,
Yuhung

PCON?
what are you using in the other end

PCON?
It is not setting in source code.
Should I set it a value?

the other end....
I use PC COM1 with
Windows hyperTerminal
(C:\Program Files\Windows NT\hypertrm.exe)

the setting is 9600 / 8 / N / 1 / N(flow control?)

PS. I use the windowsXP which is Non-English version.
so, I am not sure it is "flow control".

Regasrd.

I am try to send data with Hyper Ternimal
9600/8/n/1/n

Send->"abcdefghijklmnopqrestuvwxyz"
Receive->"yz{|}~hijklmnoxyz}{|}~xyz"

"I am try to send data with Hyper Ternimal
9600/8/n/1/n

Send->"abcdefghijklmnopqrestuvwxyz"
Receive->"yz{|}~hijklmnoxyz}{|}~xyz"z""

Looks like your baudrate is slightly out. Are you using a 12MHz crystal? The reload value in the code you are using is for an 11.0592MHz crystal. There is a baudrate calculator on this website that will let you calculate the correct values.

Alternatively, why don't you use the internal baudrate generator on the ED2?

hi Stefan Duncanson

I'm using 11.0592MHz crystal.

and ATMEL's web have following codes.
1.C51 UART Mode1 Internal Baud Rate Generator (23 KB, updated 06/04)
2.C51 UART Mode1 Timer1 (24 KB, updated 06/04)
3.C51 UART Mode1 Timer2 (22 KB, updated 06/04)

they can't send data back correctly. >_<
I tried it, but cant work.

here has some talk about this question.
http://www.grote.net/bascom/frm22321.html

but im not sure how to make it success in hyper terminal.

"I'm using 11.0592MHz crystal"

Maybe hyperterminal is your problem - try using a different terminal emulator such as TeraTerm.

"they can't send data back correctly."

Do you get the same result with all three programs?

Are you typing the characters one by one into hyperterminal, and if not, what happens if you do?

i download TeraTerm and test it.
the 3 examples are same result.

send=>"1234567890"
receive=>"9:;<=>?898"

PS. using 115200 in "3.C51 UART Mode1 Timer2"

software setting it that send a byte one by one.
(HyperTerminal and TeraTerm)

I dont know where the problem is.....>_<

PC COM1<-->HIN232<-->AT89C51ED2
Source code => from ATMEL

I use C51 UART Mode1 Timer1 (24 KB, updated 06/04) 9600bps
later
PS. using 115200 in "3.C51 UART Mode1 Timer2"

which is it?

software setting it that send a byte one by one.
thus you have changed something. if you are running 115k you need be careful that the processing is not too slow

Erik