s1r72900 Epson Electronics America, Inc., s1r72900 Datasheet - Page 39

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

7.4.3 LinkOn
The SIR72900F00A recognizes that the Link layer controller IC is inactive when it recognizes that LPS is deasserted
or the Link_Active bit of the PHY register is '0.'
LinkOn normally outputs LOW. However, the SIR72900F00A outputs a LinkOn signal when it receives a LinkOn
packet sent to the node while it recognizes that the Link layer controller IC is inactive.
If the Loop, Pwr_fail, Timeout, or Port_event bit of the PHY register changes to '1' during this period, the IC outputs
a LinkOn signal as an interrupt output.
The LinkOn signal is output as long as the Link layer controller IC is inactive. When the Link layer controller IC
becomes active, LOW is output as a LinkOn signal.
LinkOn signals are AC signals with a frequency of 6.144 MHz and a duty of 50%.
7.4.4 Link interface (LREQ, CTL[0:1], D[0:7])
The PHY/LINK interface of the SIR72900F00A complies with the IEEE 1394a-2000 standards.
The PHY/LINK interface operates in four ways, LREQ-triggered request and CTL-triggered status transmission, packet
transmission, and packet reception. The CTL-triggered operation is first controlled by the PHY.
Upon receiving a packet, the SIR72900F00A starts packet reception operation.
Figures 7.6 and 7.7 show CTL statuses and their meanings.
After the above Grant operation when the Link layer controller IC is able to control the PHY/LINK bus, the Link
interface enters the operation mode as shown in Table 7.7.
Rev. 1.0
CTL[0:1]
CTL[0:1]
00b
01b
10b
11b
00b
01b
10b
11b
Table 7.7 Operation in which the Link layer controller IC controls CTL
Operation
Operation
Reserved
Transmit
Receive
Status
Grant
Table 7.6 Operation in which the SIR72900F00A controls CTL
Hold
Idle
Idle
Idle status. The CTL is doing no operation. (Default mode)
Transmits status information.
Transmits the received packet.
Grants the Link the right to control the PHY/LINK interface for
packet transmission.
Completes the packet transmission and frees the PHY/LINK interface.
· Holds the PHY/LINK interface until the data on the packet to be
· Requests concatenated packet transmission.
Transmits data on the transmitted packet to the PHY.
Reserved.
transmitted is determined.
EPSON
Description
Description
S1R72900F00A
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