C541U_99 Datasheet, PDF (130/192 Pages) Siemens Semiconductor Group – 8-BIT CMOS MICROCONTROLLER

On-Chip Peripheral Components
C541U
One Bit Time
(12 MB/s)
Driver
Signal Pins
V _SS
Receiver
Signal Pins
V _SS
One-Way Trip Cable Delay
V _SE max
V _SE min
Signal Pins Pass
Input Spec Levels
after one Cable
Delay
MCT03414
Figure 6-36
Full Speed USB Driver Signal Waveforms
For a low speed USB connection the rise and fall time of the signals are greater than 75 ns to keep
RFI emissions under FCC class B limits, and less than 300 ns to limit timing delays and signaling
skews and distortions. The driver reaches the specified static signal levels with smooth rise and fall
times, and minimal reflections and ringing when driving the USB cable (see figure 6-37). This cable
and driver are used only on network segments between low speed devices and the ports to which
they are connected.
One Bit Time
(1.5 MB/s)
Driver
Signal Pins
V _SS
V _SE max
V _SE min
Figure 6-37
Low Speed USB Driver Signal Waveforms
Signal Pins Pass
Output Spec Levels
with minimal Reflections
and ringing
MCT03415
Semiconductor Group
6-85
1999-04-01