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— Supports enhanced host controller interface (EHCI)
— Allows direct connection of full-speed (FS) or low-speed (LS) devices without an OHCI/UHCI
companion controller
— Supported by Linux and other commercially available operating systems
•
Includes on-chip full-speed (12 Mbps), and low-speed (1.5 Mbps) transceiver
•
Allows vendor to define any USB device or class for targeted peripheral list, including USB hubs
•
Supports VBUS power enable and VBUS over-current detect to control bus power
•
Registers provided for indicating VBUS state to controller
•
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
— Integrated with the processor's doze and stop modes for ultra-low power operation
20.1.4
Modes of Operation
The USB host controller provides the functionality of one USB 2.0 host. The module is hardwired to an
on-chip full-/low-speed transceiver. Speed selection is auto-detected at connect time via sensing of the DP
or DM pullup resistor on the connected device using procedures of enumeration in the USB network. The
USB host module provides the following modes of operation for the user:
•
USB disabled. In this mode, the USB host 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 host module is integrated with the Version 3 ColdFire core's low-power modes (stop, doze and
wait). The modes are implemented as follows:
•
Stop — The processor stops the clock to the USB host module. In this state, the module ignores
traffic on the USB network and does not generate any interrupts or wake-up events. The on-chip
transceiver is disabled to save power.
•
Wait — The clocks to the USB host module are running.
•
Doze — The processor stops the system clocks to the USB host module. However, the 60 Mhz
transceiver clock remains active. Detection of resume signaling initiates a restart of the module
clocks.
20.2
External Signal Description
Table 20-1
describes the external signals of the USB host module.
Freescale Semiconductor
Section 20.1.4.1, "Low-Power Modes,"
MCF5329 Reference Manual, Rev 3
Universal Serial Bus Interface – Host Module
for details.
20-3
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