Using SmartRF studio, cc2500 can be configured to use frequency anywhere between 2400-2483.5MHz, cc1101 can be configured to use frequency anywhere between the following three range, 300-348MHz, 391-464MHz, and 782-928MHz.
Of course those are the ISM frequencies that are allowed to use. But for discussion purpose only, for example, can cc2510 operates at the 2600 MHz frequency by changing the FREQ register setting? What are the frequency range limited by the hardware per se for cc2500 and cc1101 transceivers? In other words, what sets the frequency range at the hardware level? VCO?