High-Speed Serial Interfaces (HSSI)
shows the SPI timing in master mode (internal clock).
SPICLK (output)
t
NIIVKH
t
NIIXKH
Input Signals:
SPIMISO
(See Note)
Output Signals:
SPIMOSI
(See Note)
t
NIKHOV
Note:
The clock edge is selectable on SPI.
Figure 53. SPI AC Timing in Master Mode (Internal Clock) Diagram
20 High-Speed Serial Interfaces (HSSI)
The MPC8378E features two serializer/deserializer (SerDes) interfaces to be used for high-speed serial
interconnect applications. See
for the interfaces supported.
This section describes the common portion of SerDes DC electrical specifications, which is the DC
requirement for SerDes reference clocks. The SerDes data lane’s transmitter and receiver reference circuits
are also shown.
20.1
Signal Terms Definition
The SerDes utilizes differential signaling to transfer data across the serial link. This section defines terms
used in the description and specification of differential signals.
shows how the signals are defined. For illustration purpose, only one SerDes lane is used for
description. The figure shows waveform for either a transmitter output (SDn_TX and SDn_TX) or a
receiver input (SDn_RX and SDn_RX). Each signal swings between A volts and B volts where A > B.
Using this waveform, the definitions are as follows. To simplify illustration, the following definitions
assume that the SerDes transmitter and receiver operate in a fully symmetrical differential signaling
environment.
• Single-Ended Swing
The transmitter output signals and the receiver input signals SDn_TX, SDn_TX, SDn_RX and
SDn_RX each have a peak-to-peak swing of A
–
B volts. This is also referred as each signal wire’s
single-ended swing.
•
Differential Output Voltage, V
OD
(or
Differential Output Swing):
The differential output voltage (or swing) of the transmitter, V
OD
, is defined as the difference of
the two complimentary output voltages: V
SDn_TX
–
V
SDn_TX
. The V
OD
value can be either positive
or negative.
MPC8378E PowerQUICC
™
II Pro Processor Hardware Specifications, Rev. 2
78
Freescale Semiconductor
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
