Datasheet

Universal Serial Bus Module (USB)
Functional Description
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3 Technical Data
Freescale Semiconductor Universal Serial Bus Module (USB) 129
Figure 9-7. EOP Transaction Voltage Levels
The width of the SE0 in the EOP is about two bit times. The EOP width
is measured with the same capacitive load used for maximum rise and
fall times and is measured at the same level as the differential signal
crossover points of the data lines.
Figure 9-8. EOP Width Timing
9.5.2 Reset Signaling
The USB module will detect a reset signaled on the bus by the presence
of an extended SE0 at the USB data pins of a device. The MCU seeing
a single-ended 0 on its USB data inputs for more than 8µs treats that
signal as a reset.
A USB sourced reset will hold the MCU in reset for the duration of the
reset on the USB bus. The USB bit in the reset status register (RSR) will
be set after the internal reset is removed. Refer to 8.8.2 Reset Status
Register for more detail. The MCU’s reset recovery sequence is
detailed in Section 8. System Integration Module (SIM).
BUS DRIVEN TO
LAST BIT OF
BUS IDLE
EOP
STROBE
PACKET
IDLE STATE
BUS FLOATS
V
OH
(min.)
V
SE
(max)
V
SE
(min.)
V
OL
(min.)
V
SS
EOP
WIDTH
t
Period
DIFFERENTIAL
DATA LINES
DATA
CROSSOVER
LEVEL