STLC2500A View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'STLC2500A' PDF : 37 Pages View PDF
STLC2500A
General specification
Figure 5. Low power modes [Initiated deep sleep, mode 1]
Active
BB
Sleep Mode
UART on
Host: BT_WAKEUP=‘0’=UART_RXD
AND
BT Controller: HOST_WAKEUP=‘0’
and UART_RTS=‘1’
Host: BT_WAKEUP=‘1’
OR
Hard Reset
Host: BT_WAKEUP=‘1’=UART_RXD
OR
BT Controller: HOST_WAKEUP=‘1’
(UART_RTS=‘0’)
Host: sends a specific HCI command.
Deep Sleep
Mode
UART off
Complete Power Down
2. [Initiated Deep Sleep, mode 2]
In this mode, the clock request and the host wake-up signalling have been decoupled.
These functions are now covered by 2 independant signals: the HOST_WAKEUP pin
only covers the clock request functionality, GPIO3 is used as a wakeup signal to the
Host.
This mode uses the following signals: HOST_WAKEUP (only used as a clock request
signal), BT_WAKEUP and GPIO3 (used as host wakeup signal). UART_RTS,
UART_CTS are only used to stop/allow UART activity.
– The Host wakeup procedure
A Bluetooth Controller initiated wakeup of the Host is always initiated by GPIO3.
GPIO3 signals whether the Bluetooth Controller needs the Hosts attention: only if
there are data or HCI events to be sent over the UART interface, the Bluetooth
Controller will assert GPIO3 (requesting the Hosts attention).
When the Host sees a high level on GPIO3, it must wakeup (when asleep) and
assert the UART_CTS signal, allowing the Bluetooth Controller to send data or
HCI events. When asserting GPIO3, the Bluetooth Controller will make sure the
UART is open and that the UART_RTS signal is asserted.
Note that the UART will be closed (and the UART_RTS will be deasserted) by the
Bluetooth Controller when BT_WAKEUP is low and there is no data to be sent to
the Host. In that case, GPIO3 will also be low.
– The wakeup/fall-asleep procedures for the Bluetooth Controller.
The wakeup/fall-asleep procedures for the Bluetooth Controller are always
initiated by the HOST_WAKEUP (i.e.clock request) or BT_WAKEUP signal.
– The system goes into low power as follows:
the Host sets BT_WAKEUP to '0', telling the Bluetooth Controller that it can go in
low power. The Bluetooth Controller decides to enter low power mode or not,
depending on its scheduled activity and on the number of events or data packets
to be sent to the Host. When it decides to enter low power mode (meaning that
there is no scheduled activity and that there are no data or HCI events to be sent -
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