Posted on June 01, 2007 at 08:46If 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
