K60P100M100SF2RM Datasheet, PDF (1286/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Functional Description
USBDCD_TIMER2 field descriptions (continued)
Field
Description
25–16
Time Period Before Enabling D+ Pullup
TVDPSRC_CON
Sets the amount of time (in ms) that the module waits after charging port detection before system
software should enable the D+ pullup to connect to the USB host. Valid values are 1-1023, but the USB
Battery Charging Specification requires a minimum value of 40 ms.
15–4
Reserved
This read-only field is reserved and always has the value zero.
3–0
CHECK_DM
Time Before Check of D- Line
Sets the amount of time (in ms) that the module waits after the device connects to the USB bus (software
enables the D+ pullup) until checking the state of the D- line to determine the type of charging port. Valid
values are 1-15ms.
46.5 Functional Description
The sequence of detecting the presence of and type of charging port involves several
hardware components, coordinated by system software. This collection of interacting
hardware and software is called the USB Battery Charging Subsystem. The following
figure shows the USBDCD module as a component of the subsystem. The following table
describes the components.
Standard
Host Port
or
Dedicated
Charger
or
Charging
Host Port
VBUS
VBUS_detect
System Interrupt
System
Software
USB
Bus
D
D
D Pulldown
Enable
USBDCD
Module
Control
and Status
D Pullup
Enable
USB
Controller
Pullup Enable
Command
Charge
Rate
Comm
Module _Control
Battery
Charger
IC
Device
Figure 46-8. The USB Battery Charging Subsystem
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K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.