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MC9S08JM16 Datasheet, PDF (301/386 Pages) Freescale Semiconductor, Inc – Microcontrollers
17.3.1
USB Control Register 0 (USBCTL0)
Universal Serial Bus Device Controller (S08USBV1)
7
R
0
W USBRESET
6
USBPU
5
USBRESMEN
4
LPRESF
3
2
1
0
0
USBVREN
Reset
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 17-3. USB Transceiver and Regulator Control Register 0 (USBCTL0)
0
USBPHYEN
0
Table 17-4. USBCTL0 Field Descriptions
Field
Description
7
USBRESET
USB Reset — This bit generates a hard reset of the USB module, USBPHYEN and USBVREGEN bits will also
be cleared. (need remember to restart USB Transceiver and USB voltage regulator).
When set to 1, this bit automatically clears when the reset occurs.
0 USB module normal operation
1 Returns the USB module to its reset state
6
USBPU
Pull Up Source — This bit determines the source of the pullup resistor on the USBDP line.
0 Internal USBDP pullup resistor is disabled; The application can use an external pullup resistor
1 Internal USBDP pullup resistor is enabled
5
USBRESMEN
USB Low-Power Resume Event Enable — This bit, when set, enables the USB module to send an
asynchronous wakeup interrupt to the MCU upon detection that the LPRESF bit has been set, indicating
a K-state on the USB bus. This bit must be set before entering low-power stop3 mode only after SLEEPF=1 (USB
is entering suspend mode). It must be cleared immediately after stop3 recovery in order to clear the Low-Power
Resume Flag.
0 USB asynchronous wakeup from suspend mode disabled
1 USB asynchronous wakeup from suspend mode enabled
4
LPRESF
Low-Power Resume Flag — This bit becomes set in USB suspend mode if USBRESMEN=1 and a K-state is
detected on the USB bus, indicating resume signaling while the device is in a low-power stop3 mode. This flag
bit will trigger an asynchronous interrupt, which will wake the device from stop3. Firmware must then clear the
USBRESMEN bit in order to clear the LPRESF bit.
0 No K-state detected on the USB bus while the device is in stop3 and the USB is suspended.
1 K-state detected on the USB bus when USBRESMEN=1, the device is in stop3, and the USB is suspended.
2
USBVREN
USB Voltage Regulator Enable — This bit enables the on-chip 3.3 V USB voltage regulator.
0 On-chip USB voltage regulator is disabled (OFF MODE)
1 On-chip USB voltage regulator is enabled for active or standby mode
0
USBPHYEN
USB Transceiver Enable — When the USB Transceiver (XCVR) is disabled, USBDP and USBDN are hi-Z. It is
recommended that the XCVR be enabled before setting the USBEN bit in the CTL register. The firmware must
ensure that the XCVR remains enabled when entering USB SUSPEND mode.
0 On-chip XCVR is disabled
1 On-chip XCVR is enabled
17.3.2 Peripheral ID Register (PERID)
The PERID reads back the value of 0x04. This value is defined for the USB module peripheral.
MC9S08JM16 Series Data Sheet, Rev. 2
Freescale Semiconductor
301