I use two mode of this chip in my project. And I want to desgin a low power UART communication the average current < 1mA. But I need a high speed systerm clock to run our code. And enter low power mode when there is no work to do. The UART communicate must work in both two modes.
1.run mode: Use the external reference clock and the PLL. The systerm clock is 48M and the bus clock is 24M.
2.low power mode: The VLPW mode. Use the 4M Hz IRC. The bus clock is 4M.
I need to switch the two modes frequency(probably in one UART communication). When the systerm clock changed. I need to confige the UART Baud. This could make the UART communication date lost.
Is there any way that when I change the mode the UART works fine? I don't need to confige the baud.
Or How I can make the UART clock don't change when I switch the two modes?
Thank you for your help.