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Data Sheet

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Copyright © Bridgetek Pte Ltd 39
BT81X (815/6) Advanced Embedded Video Engine Datasheet
Version 1.0
Document No.: BRT_000220 Clearance No.: BRT#126
Figure 4-13 Power State Transition
4.9.3.1 ACTIVE state
In ACTIVE state, the BT815/6 is in normal operation. The clock oscillator and PLL are functioning. The
system clock applied to the BT815/6 core engines is enabled.
4.9.3.2 STANDBY state
In STANDBY state, the clock oscillator and PLL remain functioning; the system clock applied to the
BT815/6 core engines is disabled. All register contents are retained.
4.9.3.3 SLEEP state
In SLEEP state, the clock oscillator, PLL and system clock applied to the BT815/6 core engines are
disabled. All register contents are retained.
4.9.3.4 POWERDOWN state
In POWERDOWN state, the clock oscillator, the PLL and the system clock applied to the BT815/6 core is
disabled. The core engines are powered down while the SPI interface for host commands remains
functional. All register contents are lost and reset to default when the chip is next switched on. The
internal regulator remains on.
4.9.3.5 Wake up to ACTIVE from other power states
When in the POWER DOWN state, if the device enters this state via an SPI command, then only the SPI
ACTIVE command will bring the device back to the ACTIVE state, provided PD_N pin is also high.
However, if PD_N is used instead, then making PD_N high followed by a SPI ACTIVE command will wake
up the device. Upon exiting this state, the device will perform a global reset, and will go through the
same power up sequence. All settings from SPI commands will be reset except those that pertain to pin
states during power down. The clock enable sequence mentioned in section 4.2.3 shall be executed to
properly select and enable the system clock.
POWERDOWN
SLEEP
STANDBY
VCC/VCCIO
Power ON
Toggle PD_N from high
to low
ACTIVE
Toggle PD_N from low
to high
Toggle PD_N from high
to low
Toggle PD_N from high to low or
Write command “POWERDOWN”
Write command “STANDBY”
Write command
“SLEEP”
Write command
“ACTIVE”
Write command
“ACTIVE”