RM0367 Datasheet, PDF (919/1009 Pages) STMicroelectronics – This reference manual targets application developers

Universal serial bus full-speed device interface (USB)
RM0367
Bit 15 DPPU: DP pull-up control
This bit is set by software to enable the embedded pull-up on the DP line. Clearing it to ‘0’
can be used to signalize disconnect to the host when needed by the user software.
Bits 14:8 Reserved.
Bit 7 PS2DET: DM pull-up detection status
This bit is active only during PD and gives the result of comparison between DM voltage
level and V_LGC threshold. In normal situation, the DM level should be below this threshold. If
it is above, it means that the DM is externally pulled high. This can be caused by connection
to a PS2 port (which pulls-up both DP and DM lines) or to some proprietary charger not
following the BCD specification.
0: Normal port detected (connected to SDP, ACA, CDP or DCP).
1: PS2 port or proprietary charger detected.
Bit 6 SDET: Secondary detection (SD) status
This bit gives the result of SD.
0: CDP detected.
1: DCP detected.
Bit 5 PDET: Primary detection (PD) status
This bit gives the result of PD.
0: no BCD support detected (connected to SDP or proprietary device).
1: BCD support detected (connected to ACA, CDP or DCP).
Bit 4 DCDET: Data contact detection (DCD) status
This bit gives the result of DCD.
0: data lines contact not detected.
1: data lines contact detected.
Bit 3 SDEN: Secondary detection (SD) mode enable
This bit is set by the software to put the BCD into SD mode. Only one detection mode (DCD,
PD, SD or OFF) should be selected to work correctly.
Bit 2 PDEN: Primary detection (PD) mode enable
This bit is set by the software to put the BCD into PD mode. Only one detection mode (DCD,
PD, SD or OFF) should be selected to work correctly.
Bit 1 DCDEN: Data contact detection (DCD) mode enable
This bit is set by the software to put the BCD into DCD mode. Only one detection mode
(DCD, PD, SD or OFF) should be selected to work correctly.
Bit 0 BCDEN: Battery charging detector (BCD) enable
This bit is set by the software to enable the BCD support within the USB device. When
enabled, the USB PHY is fully controlled by BCD and cannot be used for normal
communication. Once the BCD discovery is finished, the BCD should be placed in OFF
mode by clearing this bit to ‘0 in order to allow the normal USB operation.
32.6.2
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.
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