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— Supports enhanced-host-controller interface (EHCI).
— Allows direct connection of FS/LS devices without an OHCI/UHCI companion controller.
— Supported by Linux and other commercially available operating systems.
•
USB device mode
— Supports full-speed operation via the on-chip transceiver.
— Supports one upstream facing port.
— Supports four programmable, bidirectional USB endpoints, including endpoint 0. See endpoint
configurations:
Endpoint
•
Suspend mode/low power
— As host, firmware can suspend individual devices or the entire USB and disable chip clocks for
low-power operation.
— Device supports low-power suspend.
— Remote wake-up supported for host and device.
— Integrated with the processor's doze and stop modes for low power operation.
•
Includes an on-chip full-speed (12 Mbps) and low-speed (1.5 Mbps) transceiver
20.1.4
Modes of Operation
The USB OTG module has two basic operating modes: host and device. Selection of operating mode is
accomplished via the USBMODE[CM] bit field.
Speed selection is auto-detected at connect time via sensing of the DP or DM pull-up resistor on the
connected device using enumeration procedures in the USB network. The USB OTG module provides
these operation modes:
•
USB disabled. In this mode, the USB OTG's datapath does not accept transactions received on the
USB interface.
•
USB enabled. In this mode, the USB host's datapath is enabled to accept transactions received on
the USB interface.
•
USB enabled, low-power modes. See
20.1.4.1
Low-Power Modes
The USB OTG module is integrated with the processor's low-power modes (stop, doze and wait). The
modes are implemented as follows:
Freescale Semiconductor
Table 20-1. Endpoint Configurations
Type
FIFO Size
0
Bidirectional
Variable
1-3
IN or OUT
Variable
Section 20.1.4.1, "Low-Power Modes,"
MCF52277 Reference Manual, Rev. 1
Universal Serial Bus Interface – On-The-Go Module
Data Transfer
Comments
Control
Mandatory
Ctrl, Int, Bulk, or Iso
Optional
for details.
20-3
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