ST STM32G0 1 Series Reference Manual page 1292

Universal serial bus full-speed host/device interface (USB)
Bits 31:16 Reserved, must be kept at reset value.
Bit 15 DPPU_DPD: DP pull-up / DPDM pull-down
– Device mode
– Host mode
Bits 14:8 Reserved, must be kept at reset value.
Bit 7 PS2DET: DM pull-up detection status
– Device mode
Bit 6 SDET: Secondary detection (SD) status
– Device mode
Bit 5 PDET: Primary detection (PD) status
– Device mode
Bit 4 DCDET: Data contact detection (DCD) status
– Device mode
Bit 3 SDEN: Secondary detection (SD) mode enable
– Device mode
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This bit is set by software to enable the embedded pull-up on DP line. Clearing it to 0 can be
used to signal disconnect to the host when needed by the user software.
This bit is set by software to enable the embedded pull-down on DP and DM lines.
This bit is active only during PD and gives the result of comparison between DM voltage
level and V threshold. In normal situation, the DM level should be below this threshold. If
LGC
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.
This bit gives the result of SD.
0: CDP detected.
1: DCP detected.
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).
This bit gives the result of DCD.
0: data lines contact not detected.
1: data lines contact detected.
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.
RM0444 Rev 5
RM0444