STMicroelectronics RM0365 Reference Manual page 1026

RM0365
Bits 15:3 BTABLE[15:3]: Buffer table
Bits 2:0 Reserved, forced by hardware to 0.
LPM control and status register (USB_LPMCSR)
Address offset: 0x54
Reset value: 0x0000
Note: If LPM is not supported, this bit is not implemented and considered as reserved. Please
refer to Section 32.3: USB
15 14 13
Res. Res. Res. Res.
Bits 15:8 Reserved.
Bits 7:4 BESL[3:0]: BESL value
Bit 3 REMWAKE: bRemoteWake value
Bit 2 Reserved
Bit 1 LPMACK: LPM Token acknowledge enable
Bit 0 LPMEN: LPM support enable
Endpoint-specific registers
The number of these registers varies according to the number of endpoints that the USB
peripheral is designed to handle. The USB peripheral supports up to 8 bidirectional
endpoints. Each USB device must support a control endpoint whose address (EA bits) must
be set to 0. The USB peripheral behaves in an undefined way if multiple endpoints are
enabled having the same endpoint number value. For each endpoint, an USB_EPnR
register is available to store the endpoint specific information.
These bits contain the start address of the buffer allocation table inside the dedicated packet
memory. This table describes each endpoint buffer location and size and it must be aligned
to an 8 byte boundary (the 3 least significant bits are always '0). At the beginning of every
transaction addressed to this device, the USB peripheral reads the element of this table
related to the addressed endpoint, to get its buffer start location and the buffer size (Refer to
Structure and usage of packet buffers on page
implementation.
12 11 10 9
Res. Res. Res.
These bits contain the BESL value received with last ACKed LPM Token
This bit contains the bRemoteWake value received with last ACKed LPM Token
0: the valid LPM Token will be NYET.
1: the valid LPM Token will be ACK.
The NYET/ACK will be returned only on a successful LPM transaction:
No errors in both the EXT token and the LPM token (else ERROR)
A valid bLinkState = 0001B (L1) is received (else STALL)
This bit is set by the software to enable the LPM support within the USB device. If this bit is
at '0 no LPM transactions are handled.
Universal serial bus full-speed device interface (USB)
1008).
8 7 6
Res. BESL[3:0]
DocID025202 Rev 7
5 4 3
REM
WAKE
r r
2 1 0
LPM LPM
Res.
ACK EN
rw rw
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