USB Pin Multiplexing
14-51
Universal Serial Bus Host
Transceiverless link logic can be compared to a normal USB implementation
as shown in Figure 14–5 and Figure 14–6. Figure 14–5 shows OMAP5910
being used as a USB host controller, with the top portion of the diagram show-
ing a transceiver-based solution and the bottom portion showing a transceiver-
less solution using the OMAP5910 transceiverless link logic. Figure 14–6
shows OMAP5910 used as a USB function controller, with the top portion of
the diagram showing a transceiver-based solution and the bottom portion
showing a transceiverless solution using the OMAP5910 transceiverless link
logic.
The transceiverless link logic function in the OMAP5910 device interprets the
transmit control signals from the external USB integrated circuit and similar
signals from the OMAP5910 USB host controller or OMAP5910 USB function
controller and computes the equivalent USB differential pair state. The com-
puted differential pair state is interpreted and the appropriate transceiver out-
put signals are provided to the external USB integrated circuit and to the
OMAP5910 USB host controller or OMAP5910 USB function controller.
Figure 14–5. OMAP5910 USB Host Controller Connection—With and Without the
OMAP5910 Transceiverless Link Logic
OMAP5910
USB
function
controller
USB
transceiver
USB
type B
connector
USB
type A
connector
USB host
controller
VBUS
control
Functionality that can be modeled by OMAP5910 transceiverless
link logic
USB
transceiver
USB host
controller
USB
function
controller
Transceiverless
link logic
OMAP5910
OMAP5910
transceiverless
link logic
enabled
Without transceiverless link logic