Motorola MPC8260 - Manual (Page 656)

23-4 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part IV. Communications Processor Module
Note that the transparent controller does not automatically send the synchronization
pattern; therefore, the synchronization pattern must be included in the transmit buffer.
23.4.1.2 External Synchronization Signals
If GSMR_H[SYNL] is 0b00, the transmitter uses CTS and the receiver uses CD to begin
the sequence. These signals share two optionsÑpulsing and sampling.
GSMR_H[CDP] and GSMR_H[CTSP] determine whether CD or CTS need to be asserted
only once to begin reception/transmission or whether they must remain asserted for the
duration of the transparent frame. Pulse operation allows an uninterrupted stream of data.
However, use envelope mode to identify frames of transparent data.
The sampling option determines the delay between CD and CTS being asserted and the
resulting action by the SCC. Assume either that these signals are asynchronous to the data
and internally synchronized by the SCC or that they are synchronous to the data with faster
operation. This option allows RTS of one SCC to be connected to CD of another SCC and
to have the data synchronized and bit aligned. It is also an option to link the transmitter
synchronization to the receiver synchronization. Diagrams for the pulse/envelope and
sampling options are shown in Section 23.4, ÒAchieving Synchronization in Transparent
Mode.Ó
23.4.1.2.1 External Synchronization Example
Figure shows synchronization using external signals.