Information

41.5.2 Interrupts and events
The USBDCD module has an interrupt to alert system software of certain events, which
are listed in the following table. All events except the Phase Complete event for the Data
Pin Detection phase can trigger an interrupt.
Table 41-18. Events triggering an interrupt by sequence phase
Sequence
phase
Event Event description STATUS fields
1
Phase
description
Data Pin
Detection
Phase
Complete
The module has detected data pin contact.
No interrupt occurs: CONTROL[IF] = 0.
ERR = 0
SEQ_STAT = 01
SEQ_RES = 00
TO = 0
VBUS contact
detection
Charging Port
Detection
Phase
Complete
The module has completed the process of
identifying if the USB port is a charging port or
not.
ERR = 0
SEQ_STAT = 10
SEQ_RES = 01 or 10
TO = 0
Charging port
detection
Error The module cannot identify the type of port
because the D– line is above the USB's VLGC
threshold.
ERR = 1
SEQ_STAT = 10
SEQ_RES = 00
TO = 0
Error in charging
port detection
Charger Type
Detection
Phase
Complete
The module has completed the process of
identifying the charger type detection.
Note: The ERR flag always reads zero
because no known error conditions
are checked during this phase.
ERR = 0
SEQ_STAT = 11
SEQ_RES = 11 or 10
TO = 0
Charger type
detection
Sequence
Timeout
Error The timeout interval from the time the USB
device attaches to a USB port until it connects
has elapsed.
ERR = 1
SEQ_STAT = last value
2
SEQ_RES = last value
2
TO = 1
Charger
detection
sequence
timeout.
1. See the description of the Status register for register information.
2. The SEQ_STAT and SEQ_RES fields retain the values held at the time of the timeout error.
41.5.2.1 Interrupt Handling
Software can read which event caused the interrupt from the STATUS register during the
interrupt service routine.
An interrupt is generated only if CONTROL[IE] is set. The CONTROL[IF] bit is always
set under interrupt conditions, even if CONTROL[IE] is cleared. In this case, software
can poll CONTROL[IF] to determine if an interrupt condition is pending.
Functional description
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
948 Freescale Semiconductor, Inc.