MCBSTM32EXL Keil, MCBSTM32EXL Datasheet - Page 833

• Manufacturer Part Number: MCBSTM32EXL
• Description: BOARD EVALUATION FOR STM32F103ZE
• Manufacturer: Keil

Specifications of MCBSTM32EXL

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

RM0008
A-device host negotiation protocol
HNP switches the USB host role from the A-device to the B-device. The application must set
the HNP-capable bit in the Core USB configuration register to enable the OTG_FS controller
to perform HNP as an A-device.
Figure 282. A-device HNP
1. DPPULLDOWN = signal from core to PHY to enable/disable the pull-down on the DP line inside the PHY.
1.
2.
3.
4.
5.
DMPULLDOWN = signal from core to PHY to enable/disable the pull-down on the DM line inside the PHY.
The OTG_FS controller sends the B-device a SetFeature b_hnp_enable descriptor to
enable HNP support. The B-device’s ACK response indicates that the B-device
supports HNP. The application must set Host Set HNP Enable bit in the OTG Control
and status register to indicate to the OTG_FS controller that the B-device supports
HNP.
When it has finished using the bus, the application suspends by writing the Port
suspend bit in the Host port control and status register.
When the B-device observes a USB suspend, it disconnects, indicating the initial
condition for HNP. The B-device initiates HNP only when it must switch to the host role;
otherwise, the bus continues to be suspended.
The OTG_FS controller sets the Host negotiation detected interrupt in the OTG
interrupt status register, indicating the start of HNP.
The OTG_FS controller deasserts the DM pull down and DM pull down in the PHY to
indicate a device role. The PHY enables the OTG_FS_DP pull-up resistor to indicate a
connect for B-device.
The application must read the current mode bit in the OTG Control and status register
to determine Device mode operation.
The B-device detects the connection, issues a USB reset, and enumerates the
OTG_FS controller for data traffic.
The B-device continues the host role, initiating traffic, and suspends the bus when
done.
The OTG_FS controller sets the early suspend bit in the Core interrupt register after 3
ms of bus idleness. Following this, the OTG_FS controller sets the USB Suspend bit in
the Core interrupt register.
OTG core
DP
DM
DPPULLDOWN
DMPULLDOWN
Suspend 2
1
Host
3
4
Doc ID 13902 Rev 9
5
Device
Reset
Traffic
Traffic
USB on-the-go full-speed (OTG_FS)
6
7
8
Host
Connect
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