mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 1002

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

Functional Description
1. If the USB host has suspended the USB device, system software must configure the system to limit the current drawn from
40.5.1 The Charger Detection Sequence
The following figure illustrates the charger detection sequence in a simplified timing
diagram based on the USB Battery Charging Specification v1.1.
1002
the USB bus to 2.5 mA or less.
USBDCD Module
USB Transceiver
VBUS_detect
Component
Table 40-13. USB Battery Charger Subsystem Components
The USB transceiver contains the pullup resistor for the USB D+ signal and the pulldown
resistors for the USB D+ and D- signals. The D+ pullup and the D- pulldown are both used
during the charger detection sequence. The USB transceiver also outputs the digital state of
the D+ and D- signals from the USB bus.
The pullup and pulldown enable signals are controlled by other modules during the charger
detection sequence: The D+ pullup enable is physically output from the USB controller but is
under software control. The USBDCD module controls the D- pulldown enable.
Detects if the device has been plugged into either a standard host port, a charging host port,
or a dedicated charger.
This interrupt pin connected to the USB VBUS signal detects when the device has been
plugged into or unplugged from the USB bus. If the system requires waking up from a low
power mode upon being plugged into the USB port, this interrupt should also be a low power
wake up source. If this pin multiplexes other functions, such as GPIO, the pin should be
configured as an interrupt whenever the USB plug or unplug event is required to be detected.
Description
(continued)
MCF51JF128 Reference Manual, Rev. 2, 03/2011
Preliminary
Freescale Semiconductor, Inc.