Data processing system with protocol determination circuitry

A semiconductor device comprising:

• coin cell power domain circuitry configured to:
• receive power provided by a power management circuit;
• use the power as feedback to determine whether the power management circuit uses a toggle signal or a pulse signal to supply the power;
• provide the toggle signal at an output pad when the power management circuit uses the toggle signal;
• and
• provide the pulse signal at the output pad when the power management circuit uses the pulse signal.

A method comprising:

• receiving, in coin cell power domain circuitry, power provided by a power management circuit;
• testing, in the coin cell power domain circuitry, different combinations of the power and a power request signal to determine a signaling protocol used by the power management circuit to supply the power;
• and
• providing the power request signal based on the signaling protocol at an output pad coupled to the coin cell power domain circuitry.