SLVSDD7B August 2016 – March 2022 UCD9090A
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
This feature allows with the use of up to 3 GPIs to enable and disable any rail. This is useful for implementing system low-power modes and the Advanced Configuration and Power Interface (ACPI) specification that is used for operating system directed power management in servers and PCs. In up to 8 system states, the power system designer can define which rails are on and which rails are off. If a new state is presented on the input pins, and a rail is required to change state, it will do so with regard to its sequence-on or sequence-off dependencies.
The OPERATION command is modified when this function causes a rail to change its state. This means that the ON_OFF_CONFIG for a given rail must be set to use the OPERATION command for this function to have any effect on the rail state. The first 3 pins configured with the GPI_CONFIG command are used to select 1 of 8 system states. Whenever the device is reset, these pins are sampled and the system state, if enabled, will be used to update each rail state. When selecting a new system state, changes to the status of the GPIs must not take longer than 1 microsecond. See the UCD90xxx Sequencer and System Health Controller PMBus Command Reference for complete configuration settings of PIN_SELECTED_RAIL_STATES.
| GPI 2 STATE | GPI 1 STATE | GPI 0 STATE | SYSTEM STATE |
|---|---|---|---|
| NOT Asserted | NOT Asserted | NOT Asserted | 0 |
| NOT Asserted | NOT Asserted | Asserted | 1 |
| NOT Asserted | Asserted | NOT Asserted | 2 |
| NOT Asserted | Asserted | Asserted | 3 |
| Asserted | NOT Asserted | NOT Asserted | 4 |
| Asserted | NOT Asserted | Asserted | 5 |
| Asserted | Asserted | NOT Asserted | 6 |
| Asserted | Asserted | Asserted | 7 |