Anyone used MSP430F149 Controller??

[europus2002]

Hi All,
Does anyone have experience using MSP430F149 controller in your design?? I have couple of questions..


1) Is it ok to use External clock with this device ??

2) Why would a commercial crystal not work with this device (one is drive level)?? I tried loading with different capacitance values from 10pF all the way to 27pF and none of them worked. The design works great with DCO supplying MCLK....But i do not want DCO. I do not know why an off the shelf 4MHz crystal does not oscillate even when we run the unit in HF mode?? I tried hooking up external 3MHz oscillator source but that too failed....Currently i m loading the crystal input port with 15pF capacitors and that works fine with 32Khz crystal.... Am i missing some settings or does anyone have any suggestions / solutions why it wouldn't work with high frequency??

 

[itsmoked]

I have no experience with that part but a lot of them have configuration bits that default to particular crystal drive states. Driving an external crystal may not be enabled.

Check for config settings that will drive the crystal. Some even have low drive, and high drive, and over a certain speed you need to set the specific drive.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[TurboXS]

Our MSP430 circuit uses a 4MHz crystal plus 15pF capacitors.

You also have to select the crystal.

From the TI user manual (sorry about the loss of formatting) SLAU049d page 4-12;

Sourcing MCLK from a Crystal
After a PUC, the basic clock module uses DCOCLK for MCLK. If required,
MCLK may be sourced from LFXT1 or XT2.
The sequence to switch the MCLK source from the DCO clock to the crystal
clock (LFXT1CLK or XT2CLK) is:
1) Switch on the crystal oscillator
2) Clear the OFIFG flag
3) Wait at least 50 ?s
4) Test OFIFG, and repeat steps 1-4 until OFIFG remains cleared.
; Select LFXT1 (HF mode) for MCLK
BIC #OSCOFF,SR ; Turn on osc.
BIS.B #XTS,BCSCTL1 ; HF mode
L1 BIC.B #OFIFG,&IFG1 ; Clear OFIFG
MOV #0FFh,R15 ; Delay
L2 DEC R15 ;
JNZ L2 ;
BIT.B #OFIFG,&IFG1 ; Re–test OFIFG
JNZ L1 ; Repeat test if needed
BIS.B #SELM1+SELM0,&BCSCTL2 ; Select LFXT1CLK

regards
Peter

 

[europus2002]

Thanks all,
I will try that out....