K60P100M100SF2RM Datasheet, PDF (1299/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Chapter 46 USB Device Charger Detection Module (USBDCD)
A software reset also returns all internal logic, timers, and counters to their reset states.
State Machines return to IDLE. If the module is already active (STATUS[ACTIVE] = 1),
a software reset stops the sequence.
Note
Software should always initiate a software reset before starting
the sequence (setting the CONTROL[START] bit) to ensure the
module is in a known state.
46.6 Initialization Information
This module has been designed for minimal configuration while retaining significant
programmability. The CLOCK register needs to be initialized to the actual system clock
frequency (unless the default value already matches the system requirements).
The other registers generally do not need to be modified because they default to values
that comply with the USB Battery Charging Specification v1.1. However, several timing
parameters can be changed for a great deal of flexibility if a particular system requires it.
All module configuration must occur before initiating the charger detection sequence.
Configuration changes made after setting the CONTROL[START] bit result in undefined
behavior.
46.7 Application Information
This section provides application information.
46.7.1 External Pullups
Any external pullups applied to the USB D+ or D- data lines must be capable of being
disabled to prevent incorrect pullup values or incorrect operation of the USB subsystem.
46.7.2 Dead or Weak Battery
According to the USB Battery Charging Specification v1.1, a USB device with a dead,
weak, or missing battery that is attached to a charging port can remain attached
indefinitely drawing up to 1.5A until the battery is charged to the point that the USB
device can connect.
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.
1299