Information

Writes to CONTROL[IF] are ignored. To reset CONTROL[IF], set CONTROL[IACK] to
acknowledge the interrupt. Writing to CONTROL[IACK] when CONTROL[IF] is
cleared has no effect.
41.5.3 Resets
There are two ways to reset various register contents in this module: hardware resets and
a software reset.
41.5.3.1 Hardware resets
Hardware resets originate at the system or device level and propagate down to the
individual module level. They include start up reset, low-voltage reset, and all other
hardware reset sources.
Hardware resets cause the register contents to be restored to their default state as listed in
the register descriptions.
41.5.3.2 Software reset
A software reset re-initializes the module's status information, but leaves configuration
information unchanged. The software reset allows software to prepare the module
without needing to reprogram the same configuration each time the USB device is
plugged into a USB port.
Setting CONTROL[SR] initiates a software reset. The following table shows all register
fields that are reset to their default values by a software reset.
Table 41-19. Software reset and register fields affected
Register Fields affected Fields not affected
CONTROL
1
IF IE, START
STATUS All None
CLOCK None All
TIMERn TUNITCON All other
1. CONTROL[SR] and CONTROL[ IACK] are self-clearing.
A software reset also returns all internal logic, timers, and counters to their reset states. If
the module is already active (STATUS[ACTIVE] = 1), a software reset stops the
sequence.
Chapter 41 USB Device Charger Detection Module (USBDCD)
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 949