MC9S08JM16 Datasheet, PDF (299/386 Pages) Freescale Semiconductor, Inc – Microcontrollers

Mode
Stop3
Wait
Universal Serial Bus Device Controller (S08USBV1)
Table 17-2. Operating Modes (continued)
Description
The USB module is optionally available in stop3.
A reduced current consumption mode may be required for USB suspend mode per USB Specification Rev. 2.0,
and stop3 mode is useful for achieving lower current consumption for the MCU and hence the overall USB
device. Before entering stop3 via firmware, the user must ensure that the device settings are configured for
stop3 to achieve USB suspend current consumption targets.
The USB module is notified about entering suspend mode when the SLEEPF flag is set; this occurs after the
USB bus is idle for 3 ms. The device USB suspend mode current consumption level requirements are defined
by the USB Specification Rev. 2.0 (500 μA for low-power and 2.5 mA for high-power with remote-wakeup
enabled).
If USBRESMEN in USBCTL0 is set, and a K-state (resume signaling) is detected on the USB bus, the LPRESF
bit in USBCTL0 will be set. This triggers an asynchronous interrupt that will wakeup the MCU from stop3 mode
and enable clocks to the USB module. The USBRESMEN bit must then be cleared immediately after stop3
recovery to clear the LPRESF flag bit.
USB module is operational.
17.1.6 Block Diagram
Figure 17-2 is a block diagram of the USB module.
48 MHz Reference Clock
24 MHz Clock (bus clk)
USB CONTROLLER
IRQ
USB RAM
256 bytes
Serial Interface Engine
(SIE)
Enable
USBDP Pullup
BVCI
Target
TX
Logic
Protocol and Rate
Match
XCVR
BVCI
Initiator
RX
Logic
VREG
USBDP
USBDN
V_USB33
Figure 17-2. USB Module Block Diagram
MC9S08JM16 Series Data Sheet, Rev. 2
Freescale Semiconductor
299