MC68HC908JW32_09 Datasheet, PDF (155/232 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

USB Module Registers
11.5.1 USB Control Register (USBCR)
Address:
Read:
Write:
Reset:
$0051
Bit 7
USBEN
0
6
5
4
3
2
USBCLK-
EN
TC4IE
TC3IE
TC2IE TFC1IE
0
0
0
0
0
Figure 11-3. USB Control Register
1
TC0IE
0
Bit 0
0
RESUME
0
USBEN — USB Module Enable
This read/write bit enables the USB module. Setting this bit updates the endpoint configuration
according to the definition defined in UEPxCSR, UINTFCR, UEP12BPR and UEP34BPR registers.
User must ensure the 48MHz clock source is ready before the module is enabled. When the USBEN
bit is returned to zero, the module is reset and the device is returned to power state. User is
recommended to reset all the status flags by software before enabling USBEN again. Reset clears this
bit.
1 = USB module enabled
0 = USB module disabled
USBCLKEN — USB Clock Enable
This read/write bit enables the 48MHz clock source to the USB module. User must ensure this bit is
set before setting USBEN bit. In USB suspend mode it is recommended to clear this bit for power
saving. Reset clears this bit.
1 = USB clock enabled
0 = USB clock disabled
TCxIE — Transfer complete interrupt enable for endpoint x
The read/write bit enables CPU interrupt when transfer complete flag (TFRC) of corresponding
endpoint is set. TC0IE is controlling both TFRC0_IN and TFRC0_OUT at the same time. Reset clears
this bit.
1 = Transfer complete interrupt enabled
0 = Transfer complete interrupt disabled
RESUME — Force RESUME condition
This write-only bit forces a resume state (K or non-idle state) onto the USB bus data lines to initiate a
remote wakeup. This bit generates RESUME only if the device is in SUSPEND mode and the remote
wake up feature is enabled by the SET_FEATURE command. The USB control logic ensures the
forced resume duration is greater than 3ms. Reading this bit always returns zero. Writing zero to the
bit has no effect.
1 = Generates forced RESUME condition on the USB data lines
0 = Default value
MC68HC908JW32 Data Sheet, Rev. 6
Freescale Semiconductor
155