mc68hc908jb16 Freescale Semiconductor, Inc, mc68hc908jb16 Datasheet - Page 178

• Manufacturer Part Number: mc68hc908jb16
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Universal Serial Bus Module (USB)
11.7.2.1 Output Driver Characteristics
11.7.2.2 Low Speed (1.5 Mbps) Driver Characteristics
Technical Data
178
The USB transceiver uses a differential output driver to drive the USB
data signal onto the USB cable. The static output swing of the driver in
its low state is below the V
its high state is above the V
output swings between the differential high and low state are well
balanced to minimize signal skew. Slew rate control on the driver is used
to minimize the radiated noise and cross talk. The driver’s outputs
support 3-state operation to achieve bidirectional half duplex operation.
The driver can tolerate a voltage on the signal pins of –1.0V to 5.5V with
respect to local ground reference without damage.
The rise and fall time of the signals on this cable are greater than 75ns
and less than 300ns. The edges are matched to within
RFI emissions and signal skew.
USB data transmission is done with differential signals. A differential
input receiver is used to accept the USB data signal. A differential 1 on
the bus is represented by D+ being at least 200mV more positive than
D– as seen at the receiver, and a differential 0 is represented by D–
being at least 200mV more positive than D+ as seen at the receiver. The
signal cross over point must be between 1.3V and 2.0V.
V
V
SE
SE
(max)
(min.)
V
SS
Universal Serial Bus Module (USB)
Figure 11-11. Receiver Characteristics
(1.5 Mb/s)
ONE BIT
TIME
OL
OH
of 0.3V with a 1.5kΩ load to 3.6V and in
of 2.8V with a 15kΩ load to ground. The
REFLECTIONS AND RINGING
LEVELS WITH MINIMAL
PASS OUTPUT SPEC
SIGNAL PINS
MC68HC908JB16
Freescale Semiconductor
±
20% to minimize
—
Rev. 1.1