Datasheet

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7. Power Management

Power Supply Modes and Schemes

In the EOS S3 platform, there are 31 power islands, which includes the always-on domain. All of the power domains can

be independently powered on and off by power management logic, with the exception of the always-on power domain.

This allows for additional power savings obtained using software and hardware control through PMU registers.

Out of reset, the following domains are powered ON by default:

• M4-F Subsystem

• Configuration DMA/SPI Flash Controller (A1)

• 16 M4-F SRAM (32x8K) domains

• Always-on domain (cannot be powered off)

The other domains are set to OFF by default after reset release. Refer to the following figure for a listing of switchable power

domains. Additionally, some power domains also have a retention power rail, allowing retention of the state within the

domain. This capability allows the main power supply to be turned off to the domain, while still keeping the retention

power supply on. In addition to an on/off power state, some power domains may support the retention mode. While in the

retention mode, the power domains can retain the state information, but may not be accessible for read/write

operations.

The following figure shows the list of power domains, default power states and retention modes.

Table 9: Power Domains

No. Power Domain Default Power

State

On/Off Mode Retention Mode

1 On-Chip Programmable Logic Off Yes Yes

2 M4-F Subsystem (M4) On Yes No

3 Packet FIFO Bank (PKFB) Off Yes Yes

4 Configuration DMA / SPI Flash (A1) On Yes Yes

5 System DMA (SDMA) Off Yes Yes

6 Flexible Fusion Engine (FFE) Off Yes Yes, Partial

S Slave

Off Yes No

8 32x8K SRAM Instance 0 On Yes Yes

9 32x8K SRAM Instance 1 On Yes Yes

10 32x8K SRAM Instance 2 On Yes Yes

11 32x8K SRAM Instance 3 On Yes Yes

12 32x8K SRAM Instance 4 On Yes Yes

13 32x8K SRAM Instance 5 On Yes Yes

14 32x8K SRAM Instance 6 On Yes Yes

15 32x8K SRAM Instance 7 On Yes Yes

16 32x8K SRAM Instance 8 On Yes Yes

17 32x8K SRAM Instance 9 On Yes Yes

18 32x8K SRAM Instance 10 On Yes Yes

19 32x8K SRAM Instance 11 On Yes Yes