Information
Table 43-14. Overview of the Charger Detection Sequence
Phase Overview Description Full Description
1 Initial Conditions Initial system conditions that need to be met before initiating the detection
sequence
Initial System
Conditions
2 VBUS Detection System software detects contact of the VBUS signal with the system interrupt
pin VBUS_detect.
VBUS Contact
Detection
3 Data Pin Contact
Detection
The USBDCD module detects that the USB data pins D+ and D– have made
contact with the USB port.
Data Pin Contact
Detection
4 Charging Port
Detection
The USBDCD module detects if the port is a standard host or either type of
charging port (charging host or dedicated charger).
Charging Port
Detection
5 Charger Type
Detection
If attached to a charging port, detect which type. Charger Type
Detection
6 Sequence
Timeout
The USBDCD module did not finish the detection sequence within the timeout
interval. The sequence will continue until halted by software.
Charger
Detection
Sequence
Timeout
Timing parameter values used in this module are listed in the following table.
Table 43-15. Timing Parameters for the Charger Detection Sequence
Parameter USB Battery Charging Spec Module Default Module Programmable Range
T
DCD_DBNC
1
10 ms min (no max) 10 ms 0 - 1023 ms
T
VDPSRC_ON
1
40 ms min (no max) 40 ms 0 - 1023 ms
T
VDPSRC_CON
1
40 ms min (no max) 40 ms 0 - 1023 ms
CHECK_DM N/A 1 ms 0 - 15 ms
T
SEQ_INIT
N/A 16 ms 0 - 1023 ms
T
UNIT_CON
1
1 s N/A N/A
T
VDMSRC_EN
1
1 - 20 ms From the USB host N/A
T
VDMSRC_DIS
1
0 - 20 ms From the USB host N/A
T
CON_IDPSINK_DIS
1
0 - 20 ms From the USB host N/A
1. This parameter is defined by the USB Battery Charging Specification, v1.1.
43.5.1.1 Initial System Conditions
Before starting the USBDCD module's charger detection sequence, the system must be:
• using a rechargable battery,
• for a FS USB device application (cannot be HS, LS, host, or OTG),
• powered-up and in run mode,
Chapter 43 USB Device Charger Detection Module (USBDCD)
K20 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc. 1103