ST7LITE39

[heiko239955_st]

Posted on June 01, 2007 at 08:46

ST7LITE39

[heiko239955_st]

Posted on June 01, 2007 at 05:44

Hello together!

I have a problem with the configuration with

the oszillator setup. I want to start the

MCU with 8Mhz on the fcpu.

I need the Pll and the CPU voltage about 5VDC.

The MCO will be enabled with 4 MHz.

I write the Code in C.

I can't find the option bytes for the Pll.

Can you help me please?

[fggnrc]

Posted on June 01, 2007 at 08:46

If I understand the meaning of your post, you want to clock the ST7FLITE39 from an external crystal that resonates at 8 MHz.

If it is true, the MCO pin should output a 4 MHz square wave, since the signal from the crystal attached to OSC1 and OSC2 is divided by 2 (see Figure 13, page 25 of datasheet).

To have fcpu = 8 MHz, you have two options: use a 16 MHz crystal, or use the internal RC oscillator and the PLLx8.

All these setup options are encoded in the flash options bytes that are shown at pages 162-163 of the datasheet.

To change these settings, you need only to check some option in your programming device.

Regards

EtaPhi