SparkFun Forums

[aristos87]

Witch is the maximum DCO frequency that i can get on MSP430F1232 without using any external crystal? I found on user guide this commands

DCOCTL |= DCO0+DCO1+DCO2;
BCSCTL1 |= RSEL0+RSEL1+RSEL2;

They talking about setting the maxmimum DCO freq.

Also i try to mesure the freq on pin 25 (P1.4) but i get a wrong signal maybe from my usb programmer (MSP-FET430UIF) that never change.


Thanks

[swarf_maker]

<<Witch is the maximum DCO frequency that i can get on MSP430F1232 without using any external crystal? >>

It probably varies considerably from part to part , but should be somewhere in the vicinity of 8MHz. See Fig. 4-5 in the MSP430x1xx User's Guide.

<<Also i try to mesure the freq on pin 25 (P1.4) but i get a wrong signal maybe from my usb programmer (MSP-FET430UIF) that never change>>

Have you set P1SEL ad P1DIR to make the connection from SMCLK to P1.4?

[OldCow]

According to F1232 Datasheet, with no external Rosc, Rsel=7, DCO=7, and at free-air 25 C, you get min. 4, typ. 4.5, max.4.9 MHz at Vcc=2.2V and min, 4.4, typ. 4.9, max. 5.4 MHz at Vcc=3V

If you add a good 100K external pull-up resistor at P2.5/Rosc and set DCOR bit in BCSCTL2, you can get much high DCO frequencies. The frequency dependency on temperature and Vcc are also much smaller.

To show SMCLK at P1.4, you need to set BIT4 of P1DIR and P1SEL. You also need to disconnect your JTAG tool,