mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 1011

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

40.5.1.6 Charger Detection Sequence Timeout
The maximum time to connect allowed under the USB Battery Charging Specification,
v1.1 is one second. If the Unit Connection Timer reaches the one second limit and the
sequence is still running (indicated by the STATUS[ACTIVE] bit still being set), the
module does the following:
At this point, control has been passed to system software via the interrupt, which has two
options: ignore the interrupt and allow more time for the sequence to complete, or halt the
sequence. To halt the sequence, software should:
This timeout function is also useful in case software does not realize that the user
unplugged the USB device from the USB port during the charger detection sequence. If
the interrupt occurs but the V
module.
System software might allow the sequence to run past the timeout interrupt under these
conditions:
Freescale Semiconductor, Inc.
1. Read the STATUS register.
2. Set the CONTROL[IACK] bit to acknowledge the interrupt.
3. Set the CONTROL[SR] bit to issue a software reset to the module.
4. Disable the module.
1. the USB Battery Charging Spec is amended to allow more time. In this case,
2. for debug purposes.
• Updates the STATUS register to reflect that a timeout error has occured. (See
• Sets the CONTROL[IF] bit.
• Generates an interrupt if enabled (the CONTROL[IE] bit is set).
• The detection sequence continues until explicitly halted by software setting the
• The Unit Connection Timer continues counting. See the description of the TIMER0
40-18
CONTROL[SR] bit.
Register.
software should poll the T
Register) periodically to track elapsed time after 1s; or
for field values.)
MCF51JF128 Reference Manual, Rev. 2, 03/2011
BUS_DETECT
UNITCON
register field (see the description of the TIMER0
Preliminary
input is low, software can disable and reset the
Chapter 40 USB Device Charger Detection Module (USBDCD)
Table
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