Hi,
i'm using the MSP430F149 with 32.768 kHz MCLK without problems.
This makes the MC really slow but it works.
Rolf
janko20022001 schrieb:
>Somewhere I've read, that it's not
possible to source MCLK from 32kHz
>crystal. Try source MCLK from DCO and peripheral from ACLK.
>
>Jano
>
>--- In msp430@msp4..., "Jan Stumpf" <jan@e...> wrote:
>
>
>>Hi!
>>
>>I have problems to run the MSP430F1121 with a 32khz watch crystal.
>>
>>
>It
>
>
>>oscillates only with an amplitude of 300mV around VCC. I have
>>
>>
>connected the
>
>
>>crystal without external capacitators and used the following code
>>
>>
>to
>
>
>>activate the LF mode :
>>
>>void vClockInit( void ){
>> WDTCTL = WDTPW + WDTHOLD; /* disable Watchdog */
>> BCSCTL1 &= ~0x30; //select low-frequencymode, ACKL-
>>
>>
>Divider >
>
>>1
>> BCSCTL2 = 0xC8; /* set MCLKLK*/
>> }
>>
>>I also added external capacitators (33pF), but I achieved the same
>>
>>
>results.
>
>
>>Does anybody has a sample code for running the LFXT1 in LF-mode for
>>
>>
>the gcc
>
>
>>compiler? Is it necessary to add the 5.1M resistor? (Vcc=3V)
>>
>>Thanks in advance
>>
>>best regards
>>Jan
>>
>>
>
>
>
>.
>
>
>Yahoo! Groups Links
>
>
>
>
>
>
>
>
At 12:55 PM 19/04/2004, you wrote:
In the user guide - slau049d.pdf, page 124, there is a software routine for
setting the MCLK from LFTxtal.
Good luck
Peter
>Somewhere I've read, that it's not
possible to source MCLK from 32kHz
>crystal. Try source MCLK from DCO and peripheral from ACLK.
>
>Jano
>
>--- In msp430@msp4..., "Jan Stumpf" <jan@e...> wrote:
> > Hi!
> >
> > I have problems to run the MSP430F1121 with a 32khz watch crystal.
>It
> > oscillates only with an amplitude of 300mV around VCC. I have
>connected the
> > crystal without external capacitators and used the following code
>to
> > activate the LF mode :
> >
> > void vClockInit( void ){
> > WDTCTL = WDTPW + WDTHOLD; /* disable Watchdog */
> > BCSCTL1 &= ~0x30; //select low-frequencymode,
ACKL-
>Divider > > 1
> > BCSCTL2 = 0xC8; /* set MCLKLK*/
> > }
> >
> > I also added external capacitators (33pF), but I achieved the same
>results.
> > Does anybody has a sample code for running the LFXT1 in LF-mode for
>the gcc
> > compiler? Is it necessary to add the 5.1M resistor? (Vcc=3V)
> >
> > Thanks in advance
> >
> > best regards
> > Jan
>
>
>
>.
>
>
>Yahoo! Groups Links
>
>
>
>
Reply by janko20022001●April 19, 20042004-04-19
Somewhere I've read, that it's not possible to source MCLK from
32kHz
crystal. Try source MCLK from DCO and peripheral from ACLK.
Jano
--- In msp430@msp4..., "Jan Stumpf" <jan@e...> wrote:
> Hi!
>
> I have problems to run the MSP430F1121 with a 32khz watch crystal.
It
> oscillates only with an amplitude of 300mV around
VCC. I have
connected the
> crystal without external capacitators and used
the following code
to
> activate the LF mode :
>
> void vClockInit( void ){
> WDTCTL = WDTPW + WDTHOLD; /* disable Watchdog */
> BCSCTL1 &= ~0x30; //select low-frequencymode, ACKL-
Divider > 1
> BCSCTL2 = 0xC8; /* set
MCLKLK*/
> }
>
> I also added external capacitators (33pF), but I achieved the same
results.
> Does anybody has a sample code for running the
LFXT1 in LF-mode for
the gcc
> compiler? Is it necessary to add the 5.1M
resistor? (Vcc=3V)
>
> Thanks in advance
>
> best regards
> Jan
Reply by Jan Stumpf●April 17, 20042004-04-17
Hi!
I have problems to run the MSP430F1121 with a 32khz watch crystal. It
oscillates only with an amplitude of 300mV around VCC. I have connected the
crystal without external capacitators and used the following code to
activate the LF mode :
void vClockInit( void ){
WDTCTL = WDTPW + WDTHOLD; /* disable Watchdog */
BCSCTL1 &= ~0x30; //select low-frequencymode, ACKL-Divider 1
BCSCTL2 = 0xC8; /* set MCLKLK*/
}
I also added external capacitators (33pF), but I achieved the same results.
Does anybody has a sample code for running the LFXT1 in LF-mode for the gcc
compiler? Is it necessary to add the 5.1M resistor? (Vcc=3V)
Thanks in advance
best regards
Jan