If PRESW_MODE is equal to '0' the b

If PRESW_MODE is equal to '0' the bit PRESW_LF controls the weak and the strong pre-switches directly. It is possible to activate and deactivate the pre-switches with one write access.If the bit PRESW_MODE is equal to '1' the weak and the strong pre-switch can be activated and deactivated in a sequence. If a '1' is written to PRESW_LF the weak pre-switch is activated, while the register bit PRESW_LF is not yet set. Instead a shadow flag is set, which activates the weak pre-switch. The state of the weak pre-switch can be observed via the control bit LFSTATE in this case. The strong pre-switch is finally activated, if the application writes another '1' to register PRESW_LF. The de-activation follows the same procedure: The first '0' deactivates the strong pre-switch and the second '0' the weak one.The value, which is written to PRESW_MODE at the same time when PRESW_LF is written, determines the mode rather than the stored value in the register. The register content of PRESW_MODE is required to ensure the manual pre-switch control in case no strong pre-switch is activated.Example: In order to switch power supply from battery to LF field, execute the following steps:• Close the pre-switch of the LF supply by writing a '1' to PRESW_LF. The blocking capacitor at pin VDDC gets charged (if the activation of the strong pre-switch causes a too deep dip in the field supply it is also possible to close only the weak pre-switch prior to the strong one).• Wait until the voltage at VDDC has settled. The waiting time shall be properly determined for specific capacitance values and field strengths by the user.• Set the bit PWRFLD to '1' to commutate from battery supply to field supply.