STA2500DTR STMICROELECTRONICS [STMicroelectronics], STA2500DTR Datasheet - Page 36

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

General specification
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Figure 11. Entering deep sleep mode, pending data on UART interface, through
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BT_W AK EUP
BT_W AK EUP
REF_CLK _IN
REF_CLK _IN
UART_RTS
UART_RTS
UART_RTS
UART_RTS
H O ST_W AK EUP
H O ST_W AK EUP
CLK _REQ _O UT_1
CLK _REQ _O UT_1
BT_HOST_WAKEUP to ‘1’ in order to warm the Host and traffic starts when the Host
puts BT_UART_CTS to low. This is illustrated in
Autonomous wake-up with communication (i.e. initiated by the STA2500D)
The STA2500D first asks the Host to restart the system clock by setting
BT_CLK_REQ_OUT_1 to ‘1’.
When the clock is available, the STA2500D requests traffic by asserting
HOST_WAKEUP high. Then either it puts BT_UART_RTS low to start traffic exchange
directly or it waits for the Host to first assert BT_WAKEUP high. The selection in
between the two behaviours is done by a SW parameter in the Parameter File.
An autonomous wake-up without communication (i.e. initiated by the STA2500D)
The STA2500D asks the Host to restart the system clock by setting
BT_CLK_REQ_OUT_1 to ‘1’. The UART signals are not changing.
Host puts BT_WAKEUP low. BT Controller notices it. But as there is pending traffic to
be send to Host, it keeps HOST_WAKEUP high as long as needed for up-transmission
and then de-asserts HOST_WAKEUP, telling the Host there is nothing more to
transmit.
BT Controller puts UART_RTS high to set “flow off”. This is done in fixed number of
instructions.
Then BT Controller puts CLK_REQ_OUT_1 to ‘0’, telling the Host it can cut the clock.
This is done in fixed number of instructions.
There is no clock, BT is in Deep Sleep mode.
UART with handshake
Doc ID 16067 Rev 1
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STA2500D