Programmable power supply systems and methods providing a write

Abstract

A programmable power controller controls power between a primary power source and a secondary power source and powering first circuitry. The primary power source has a first voltage and the secondary power source has a second voltage. A control register has a first field, which is field used to activate circuitry used to direct power from the primary power source to the secondary power source. First logic circuitry compares the first voltage and the second voltage to determine which is greater and then couples the primary power source or the secondary power source, depending upon which is greater, to power the first logic circuitry, second logic circuitry, and memory. The memory is coupled to the first logic circuitry and is read and written to via an input/output buffer. The second logic circuitry is coupled to the memory and to said first logic circuitry and activates write protection circuitry to prevent writing to the memory if the secondary power source is powering the first logic circuitry, the second logic circuitry, and the memory.