STA2500DTR STMICROELECTRONICS [STMicroelectronics], STA2500DTR Datasheet - Page 34

• Manufacturer Part Number: STA2500DTR
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

General specification
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Figure 9.
Deep sleep mode entry and wake-up through H4 SPI
It requires BT_CLK_REQ_OUT_x (BT_CLK_REQ_OUT_1 for active high polarity and
BT_CLK_REQ_OUT_2 for active low polarity), BT_WAKEUP and BT_SPI_INT. The
BT_WAKEUP is used as wake-up signal from the Host, the BT_CLK_REQ_OUT_x requires
the clock from the Host and BT_SPI_INT is used as a wake-up signal from the Bluetooth
Controller.
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Deep sleep mode entry
The Host tells the STA2500D that it can go in Deep Sleep mode by forcing the
BT_WAKEUP of the STA2500D to ‘0’. The STA2500D decides to go in Deep Sleep
mode, or not, depending on its scheduled activity and on the number of events or data
packets to be sent to the Host. In case it decides to go in Deep Sleep mode, it asserts
BT_CLK_REQ_OUT_x ‘inactive’ to tell the Host that it does not need the clock
anymore. The STA2500D cannot go in Deep Sleep mode by itself. Note that the Host
cannot force BT_WAKEUP to ‘0’ before the end of a write operation from the Host, this
in order to allow correct decoding of the message by the Bluetooth Controller.
Deep sleep mode wake-up
The wake-up procedure can be initiated by the Host or by the STA2500D. In the latter
case, it can be with or without communication, depending if there are data to be
transmitted to the Host.
Wake-up initiated by the Host
The Host sets the BT_WAKEUP pin of the STA2500D to ‘1’. Then the STA2500D asks
the Host to restart the system clock by setting BT_CLK_REQ_OUT_x to ‘active’. When
the clock is available and stable, the Host can use BT_SPI_CSN to start an SPI
transaction if needed (there is a programmable minimum delay between the assertion
of BT_CLK_REQ_OUT_x and the moment the Host can assert BT_SPI_CSN).
Autonomous wake-up with SPI communication (i.e. initiated by the STA2500D)
The STA2500D first asks the Host to restart the system clock by setting
BT_CLK_REQ_OUT_x to ‘active’.
When the clock is available, the STA2500D sets BT_SPI_INT high to request the SPI
interface to the Host and waits for BT_SPI_CSN going low, indicating the SPI
transaction starts.
Autonomous wake-up without SPI communication (i.e. initiated by the STA2500D)
The STA2500D asks the Host to restart the system clock by setting
BT_CLK_REQ_OUT_x to ‘active’.
SPI_CSN
SPI_CLK
SPI_INT
REF_CLK _IN
CLK _REQ _ OUT_1
SPI_DO
SPI_DI
Wake-up by the Bluetooth controller with data transmission to the host,
through enhanced H4 SPI
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Doc ID 16067 Rev 1
DATA
STA2500D