MPC8313E-RDBB Freescale Semiconductor, MPC8313E-RDBB Datasheet - Page 37

• Manufacturer Part Number: MPC8313E-RDBB
• Description: BOARD CPU 8313E VER 2.1
• Manufacturer: Freescale Semiconductor
• Series: PowerQUICC II™ PROr
• Type: MPUr

Specifications of MPC8313E-RDBB

• Contents: Board
• Processor To Be Evaluated: MPC8xxx
• Data Bus Width: 32 bit
• Interface Type: Ethernet, USB, JTAG, SPI, UART
• Dimensions: 170 mm x 170 mm
• Operating Supply Voltage: 3.3 V
• For Use With/related Products: MPC8313E
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

To illustrate these definitions using real values, consider the case of a CML (current mode logic)
transmitter that has a common mode voltage of 2.25 V and each of its outputs, TD and TD, has a swing
that goes between 2.5 and 2.0 V. Using these values, the peak-to-peak voltage swing of each signal (TD or
TD) is 500 mV p-p, which is referred as the single-ended swing for each signal. In this example, since the
differential signaling environment is fully symmetrical, the transmitter output’s differential swing (V
has the same amplitude as each signal’s single-ended swing. The differential output signal ranges between
500 and –500 mV, in other words, V
differential voltage (V
Freescale Semiconductor
4. Differential peak voltage, V
5. Differential peak-to-peak, V
6. Differential waveform
7. Common mode voltage, V
The peak value of the differential transmitter output signal or the differential receiver input signal
is defined as differential peak voltage, V
Since the differential output signal of the transmitter and the differential input signal of the receiver
each range from A – B to –(A – B) volts, the peak-to-peak value of the differential transmitter
output signal or the differential receiver input signal is defined as differential peak-to-peak voltage,
V
twice of the differential peak. For example, the output differential peak-peak voltage can also be
calculated as V
The differential waveform is constructed by subtracting the inverting signal (TXn, for example)
from the non-inverting signal (TXn, for example) within a differential pair. There is only one signal
trace curve in a differential waveform. The voltage represented in the differential waveform is not
referenced to ground. Refer to
The common mode voltage is equal to one half of the sum of the voltages between each conductor
of a balanced interchange circuit and ground. In this example, for SerDes output, V
(V
voltages within a differential pair. In a system, the common mode voltage may often differ from
one component’s output to the other’s input. Sometimes, it may be even different between the
receiver input and driver output circuits within the same component. It’s also referred as the DC
offset in some occasion.
A Volts
B Volts
DIFFp-p
TXn
+ V
= 2 × V
TXn
Figure 22. Differential Voltage Definitions for Transmitter or Receiver
MPC8313E PowerQUICC
TX n or RX n
TX n or RX n
)/2 = (A + B)/2, which is the arithmetic mean of the two complimentary output
DIFFp
TX-DIFFp-p
DIFFp
) is 500 mV. The peak-to-peak differential voltage (V
= 2 × |(A – B)| volts, which is twice of differential swing in amplitude, or
Differential Peak-Peak Voltage, V
= 2 × |V
cm
DIFFp
OD
DIFFp-p
Figure 22
is 500 mV in one phase and –500 mV in the other phase. The peak
™
Differential Swing, V
Differential Peak Voltage, V
OD
II Pro Processor Hardware Specifications, Rev. 3
|.
DIFFp
as an example for differential waveform.
= |A – B| volts.
ID
DIFFpp
or V
OD
DIFFp
= 2*V
= A – B
= |A – B|
DIFFp
(not shown)
High-Speed Serial Interfaces (HSSI)
DIFFp-p
V
cm
) is 1000 mV p-p.
= (A + B)/2
cm_out
=
OD
37
)