s1r72900 Epson Electronics America, Inc., s1r72900 Datasheet - Page 33

• Manufacturer Part Number: s1r72900
• Description: Physical Layer Ic Compliant With The Ieee 1394-1995 And Ieee 1394a-2000 Standards.
• Manufacturer: Epson Electronics America, Inc.

7.3.4 Suspend/Resume
There are two operations for the port state to transit from Active to Suspend state.
When receiving TX SUSPEND that was output by Suspend Initiator (RX SUSPEND)
The port (the Suspend Target) that received the RX SUSPEND enters the Suspend state. The node also outputs TX
SUSPEND into Active ports other than the port that received RX SUSPEND, and the port is set as the Suspend Initiator.
The Suspend Initiator port then also enters the Suspend state.
TX SUSPEND is transmitted until the position of this leaf node to set at the Suspend state. However, if the IEEE1394-
1995 node, the Disabled port and the Suspend port are present on its way, TX SUSPEND will be transmitted to stop
at their positions. Even when the port is set at Suspend state, the Fault bit is set to indicate that the Suspend state is not
set normally when the Bias of the connection partner node was detected.
The conditions under which the port of the Suspend state starts the Resume operation to enter the Active state are as
follows.
If the Boundary node is not set, the other Suspended ports except this node will also start Resume operation
simultaneously when the ports in the Suspend or Disconnected state start Resume operation with the Bias detected (other
than Resume packet and Remote Command packet).
The Resume operation outputs TPBIAS, and it is terminated normally when the Bias of the connection partner node
is detected. It then enters the Active state. However, it returns to the Suspended state to set the Fault bit, indicating
that Resume operation was terminated normally if the Bias from the connection partner node cannot be detected.
When receiving the Resume Command packet which the Suspend bit for its own port was set to
The Remote Command packet is transferred two ways, from nodes other than its own node, and from the Link layer
controller IC, which correspondent to the upper level layer of its own node. Either way, the Remote Confirmation packet
is transferred to all ports and the PHY/LINK interface when the S1R72900F00A receives the Remote Command packet.
Bus reset is then issued to all ports other than the port (Suspend Initiator) that the Suspend bit is set to, and the node
enters the reset state. Simultaneously, the port which the Suspend bit is set to outputs TX SUSPEND and it then enters
the Suspend state.
7.3.5 Processing Unused Ports
If there are ports to be not used out of two SiR72009F00A cable ports, the pin should be processed as shown Figure 7-
12.
Rev. 1.0
–The Bias of the connection partner node is detected and the Fault bit is cleared.
–The Resume packet is received.
–The Remote Command packet, which the Resume bits for the port were set to, is received.
Figure 7.12 Processing Unused Ports
TPBIAS
TPA P
TPA N
TPB P
TPB N
EPSON
GND
1 F
S1R72900F00A
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