ST STM32L4x6 Reference Manual page 1547

RM0351
Bits 5:2 BESL: Best effort service latency
Bit 1 LPMACK: LPM token acknowledge enable
– No PID/CRC5 Errors in either EXT token or LPM token (else ERROR)
– Valid bLinkState = 0001B (L1) received in LPM transaction (else STALL)
– No data pending in transmit queue (else NYET).
– The received bLinkState is not L1 (STALL response), or
– An error is detected in either of the LPM token packets because of corruption (ERROR
Note: Accessible only in device mode.
Bit 0 LPMEN: LPM support enable
Host mode:
The value of BESL to be sent in an LPM transaction. This value is also used to initiate
resume for a duration T
L1HubDrvResume1
Device mode (read-only):
This field is updated with the received LPM token BESL bmAttribute when an ACK, NYET,
or STALL response is sent to an LPM transaction.
BESL[3:0]T (μs)
BESL
0000:125
0001:150
0010:200
0011:300
0100:400
0101:500
0110:1000
0111:2000
1000:3000
1001:4000
1010:5000
1011:6000
1100:7000
1101:8000
1110:9000
1111:10000
Handshake response to LPM token pre-programmed by device application software.
1:ACK
Even though ACK is pre-programmed, the core Device responds with ACK only on
successful LPM transaction. The LPM transaction is successful if:
0:NYET
The pre-programmed software bit is over-ridden for response to LPM token when:
response).
The application uses this bit to control the
If the core operates as a non-LPM-capable host, it cannot request the connected device or
hub to activate LPM mode.
If the core operates as a non-LPM-capable device, it cannot respond to any LPM
transactions.
0: LPM capability is not enabled
1: LPM capability is enabled
DocID024597 Rev 3
USB on-the-go full-speed (OTG_FS)
for host initiated resume.
OTG_FS
core LPM capabilities.
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