K60P100M100SF2RM Datasheet, PDF (1287/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Chapter 46 USB Device Charger Detection Module (USBDCD)
Table 46-13. USB Battery Charger Subsystem Components
Component
Battery Charger IC
Description
The external battery charger IC regulates the charge rate to the rechargable battery. System
software is responsible for communicating the appropriate charge rates.
Comm Module
System software
USB Controller
Charger
Standard host port
Charging host port
Dedicated charging port
Maximum Current Drawn¹
up to 500 mA
up to 1500 mA
up to 1800 mA
1. If the USB host has suspended the USB device, system software must configure the
system to limit the current drawn from the USB bus to 2.5 mA or less.
A communications module on the device can be used to control the charge rate of the battery
charger IC.
Coordinates the detection activities of the subsystem.
The D+ pullup enable control signal plays a role during the charger type detection phase.
System software must issue a command to the USB controller to assert this signal. Once this
pullup is enabled, the device is considered to be connected to the USB bus. The host then
attempts to enumerate it.
Note that the USB controller must be used only for USB device applications when using the
USBDCD module. For USB host applications the USBDCD module must be disabled.
USB Transceiver
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.
USBDCD Module
VBUS_detect
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.
1. If the USB host has suspended the USB device, system software must configure the system to limit the current drawn from
the USB bus to 2.5 mA or less.
46.5.1 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.
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.
1287