Prev: Brand Watches Wenger TerraGraph White Dial Strap 72700 Watch Discount, Replica, Fake
Next: MSP430-ez430 Basics - reading in pushbutton values
From: cs_posting on 21 Apr 2008 13:21
On Apr 21, 1:10 pm, Oskar <oskar.nordqu...(a)gmail.com> wrote:

> I'm trying to clock the CPU (MSP430F1611) to 8,000,000 Hz and I've run
> into
> some problems. Making the CPU to actually run at 8MHz was easy enough:

> However, the UART1 stopped working.

Speaking generally rather than about your specific chip:

Try writing a loop to send a character on the serial endlessly, and
then looking at the serial output timing on a scope.

You could also look at the timing values that worked at the old clock
rate and proportionally correct for the new one, but someones the
dividers get interesting (programmed value + 1 for example) such that
it won't quite be a linear ratio.

There's always reading the manual, but sometimes the value of the
other approaches is catching misunderstandings of what the manual was
trying to say.
From: Leon on 21 Apr 2008 13:35
On 21 Apr, 18:21, cs_post...(a)hotmail.com wrote:
> On Apr 21, 1:10 pm, Oskar <oskar.nordqu...(a)gmail.com> wrote:
>
> > I'm trying to clock the CPU (MSP430F1611) to 8,000,000 Hz and I've run
> > into
> > some problems. Making the CPU to actually run at 8MHz was easy enough:
> > However, the UART1 stopped working.
>
> Speaking generally rather than about your specific chip:
>
> Try writing a loop to send a character on the serial endlessly, and
> then looking at the serial output timing on a scope.
>
> You could also look at the timing values that worked at the old clock
> rate and proportionally correct for the new one, but someones the
> dividers get interesting (programmed value + 1 for example) such that
> it won't quite be a linear ratio.
>
> There's always reading the manual, but sometimes the value of the
> other approaches is catching misunderstandings of what the manual was
> trying to say.


'U' is a good value to send (alternating 1s and 0s).

Leon

From: dalai lamah on 21 Apr 2008 15:59
Un bel giorno Oskar digit�:

> some problems. Making the CPU to actually run at 8MHz was easy enough:
>
> DCOCTL = DCO0 + DCO1 + DCO2; /* 0xE0 */
> BCSCTL1 = XT2OFF + RSEL0 + RSEL1 + RSEL2; /* 0x87 */
>
> However, the UART1 stopped working. What I've got so far is:

The safe operating frequency of the MSP430 depends on the supply voltage;
in order to run it safely at 8 MHz you need to apply the maximum specified
voltage, i.e. 3.6 V. Maybe you are using a lower supply voltage?

--
emboliaschizoide.splinder.com
From: Oskar on 22 Apr 2008 08:53
On Apr 21, 7:21 pm, cs_post...(a)hotmail.com wrote:
> On Apr 21, 1:10 pm, Oskar <oskar.nordqu...(a)gmail.com> wrote:
>
> > I'm trying to clock the CPU (MSP430F1611) to 8,000,000 Hz and I've run
> > into
> > some problems. Making the CPU to actually run at 8MHz was easy enough:
> > However, the UART1 stopped working.
>
> Speaking generally rather than about your specific chip:
>
> Try writing a loop to send a character on the serial endlessly, and
> then looking at the serial output timing on a scope.
>
> You could also look at the timing values that worked at the old clock
> rate and proportionally correct for the new one, but someones the
> dividers get interesting (programmed value + 1 for example) such that
> it won't quite be a linear ratio.
>
> There's always reading the manual, but sometimes the value of the
> other approaches is catching misunderstandings of what the manual was
> trying to say.

I don't have a scope available at the moment, I will have to match a
set of
characters and try different register settings using some automation
technique.

Now, what registers are actually frequency dependant besides UBR01,
UBR11, and
UMCTL1?
From: cs_posting on 22 Apr 2008 12:51
On Apr 22, 8:53 am, Oskar <oskar.nordqu...(a)gmail.com> wrote:

> > Try writing a loop to send a character on the serial endlessly, and
> > then looking at the serial output timing on a scope.

> I don't have a scope available at the moment

Too bad 19200 Hz is probably beyond the range of hearing, otherwise
I'd suggest
audibly comparing the bit clock (use the 'U' suggestion) to a PC
endlessly sending
the same thing.

Maybe wire up a divider IC to knock down the frequency?

(Yeah, I realize this may not be the best course of action... but it
would be FUN!)
 |  Next  |  Last
Pages: 1 2
Prev: Brand Watches Wenger TerraGraph White Dial Strap 72700 Watch Discount, Replica, Fake
Next: MSP430-ez430 Basics - reading in pushbutton values