Re: UART is transmitting grabage on the hyper-terminal screen
The clock for the UART is actualy the bit rate. See the chapter
"Examples of Baud Rate Setting" in you microcontoller's datasheet.
For example, for atmega48 running at 1Mhz(default) for a 4800bps data
rate, set UBRR to 12. (U2xn bit is 0).
When you say you hit a key and another character writes on the
terminal, you give no info about the hardware you are using:
1)What type of microcontroller?
2)What is the wireing of the UART pins ?
3)Are you using the max232 EIA to TTL voltage level converter?
4)If so, are you using the correctly sized capacitors for this?
We cannot help you unless you take some time and write in a lot more
words the problems you are experiences and the hardware you are using.
For further reading, see
(entire URL might contain spaces, delete any spaces and copy paste in
--- In firstname.lastname@example.org,
"fourier902000" <fourier902000@...> wrote:
> --- In email@example.com, "Mihai Galos" <mihaigalos@>
> > Dear fourier,
> > Please explain yourself using more words because your english
> > prevents us from understanding you.
> > Such an UART behaviour as i think you are trying to describe at
> > can be caused by :max232
> > - capacitor values inconsistent with the datashhet for the
> > (or equivalanet) TTL to EIA sinal converter (you are using one,RIGHT
> > ?!)read
> > - high noise environment
> > - uncalibrated bit rates (refer to setting bit rates in the AVR
> > datasheet)
> > Kind regards,
> > Mihai GALOS
> > --- In firstname.lastname@example.org,
> > "fourier902000" <fourier902000@> wrote:
> > >
> > > Hello
> > > I'am in the process of writing a Uart code that is intended to
> > > sensor values and out those values a PC screen.and
> > >
> > > However the first part of the process is completed, code run
> > > compile but one thing ...correct
> > >
> > > 1) if a letter is typed from the keyboard I don't see the
> > > output. Meaning if A is pressed on the keyboard B is output onthe
> > > screen.D
> > >
> > > 2) The second part of my project is to take values from the A/
> > > registers and displayed those values on the Hyperteminal.( anyidea
> > > how to go about this ?)other
> > >
> I am sorry about my english!!
> when I type a character from the keyboard what I see is some
> character which is different from the keystroke that was depressed.
> How do you set the internal clock ?