Supported PMBus Commands describes the memory model for PMBus devices. Values used by the PMBus device are loaded into volatile operating memory from the following places:

• Values hard-coded into an IC design
• Values programmed from hardware terminals
• A non-volatile memory called the default store
• Communications from the PMBus

On-board data flash memory is used to implement the hard-coded values and the default store values. Values in the default store may be changed using the STORE_DEFAULT_ALL command described in (11h) STORE_DEFAULT_ALL. The user store is not supported. Table 8-6 describes the ordering of memory loading and precedence. In general, the hard-coded parameters are loaded into operating memory first. Second, any terminal-programmable settings take effect. Third, values from the default store are loaded. Later, commands issued from the PMBus take effect. In all cases, an operation on a parameter overwrites any prior value that was already in the operating memory.

Figure 8-26 Memory Model