Change channel frequency quickly for a frequency hopping application using ADF7024

To change the channel frequency the host processor just needs to update the RADIO_CHANNEL_FREQ_X registers (address 0x109, 0x10A and 0x10B).

The host processor can write to these registers in PHY_OFF, PHY_ON,  PHY_RX or PHY_TX. The new frequency doesn't get applied until a CMD_PHY_RX or CMD_PHY_TX is issued. Note there is no requirement to issue the CMD_CONFIG_DEV command after changing the RADIO_CHANNEL_FREQ_X registers.

So, as an example,  if the ADF7024 is in PHY_RX and needs to go to PHY_RX on a new channel frequency the host processor should follow these steps:

1. Write to registers 0x109, 0x10A and 0x10B sequentially using SPI_MEM_WR.
2. Issue CMD_PHY_RX (i.e. 0xB2). The transition from PHY_RX (on previous channel frequency) to PHY_RX (on new channel frequency) takes 339.5us typically. (Refer to the ADF7024 Reference Manual and the state transition timing for more information on the timing)