ISL35822 Datasheet, PDF (15/75 Pages) Intersil Corporation – Octal 2.488Gbps to 3.187Gbps/ Lane Retimer

ISL35822
Serial Test Loopbacks (1.C004.12 & 4.C004.12)
In addition to the above loopbacks, the ISL35822 also offers
two serial loopbacks directly between the serial inputs and
outputs. These loopbacks use the recovered clock as the
timing for the outputs (instead of the multiplied reference
clock), so do not reset the jitter or clock domains, and in
addition do NOT provide any pre-emphasis on the outputs.
Furthermore, on the PMA/PMD side (1.C004.12) the lanes
are internally swapped (so the Lane 3 output is from the
Lane 0 input, etc.). Because of their limited utility, they are
not illustrated in Figure 2 or Figure 6. They are mainly useful
for debugging an otherwise intractable system problem. The
reference clock still needs to be within locking range of the
input frequency. The remainder of the signal path will remain
active (as normal), so that if for example 1.C004.12 is set,
data coming in on RCX[3:0], in addition to emerging on
TCX[0:3] without retiming, etc., will also emerge from
TXP[3:0] retimed, as usual.
Serial Management Interface
The ISL35822 implements the MMD Management Interface
defined in IEEE 802.3-2002 Clauses 22 & enhanced in IEEE
802.3ae-2002 Clause 45. This two-pin interface allows serial
read/write of the internal control registers and consists of the
MDC clock and MDIO data terminals. The PADR[4..0] pins
are used to select the ‘Port address’ to which a given
ISL35822 device responds. The ISL35822 will ignore Clause
22 format frames (on a frame-by-frame basis), based on the
second ST (start) bit value. The two formats are shown in
Table 3, together with the references to the respective IEEE
802.3 specifications.
MDIO Register Addressing
The PADR[4..0] hardware address pins control the PRTAD
(Port Address) value, each port normally consisting of a
series of MDIO Managed Devices (MMDs). Each Port may
include up to 31 different devices, of which the current
specification defines 8 types, and allows vendor
specification of two others. The ISL35822 device
corresponds to the PMA/PMD, PCS and PHY XGXS defined
types, so responds to DEVAD values of 1, 3 and 4
respectively. The Clause 45-accessible registers are listed
for each Device Address in the tables referenced in Table 2.
Many of these register addresses are IEEE-defined; the
‘Vendor Defined’ registers are arranged to be as DEVAD
independent as possible.
Table 2. DEVAD DEVICE ADDRESS TABLE
DEVAD VALUE
IEEE DEFINITION
REGISTER LIST
TABLE
DEVAD = 1 (00001’b) PMA/PMD Device
Table 4, page 19
DEVAD = 3 (00011’b) PCS Device
Table 56, page 38
DEVAD = 4 (00100’b) PHY XS (XGXS) Device Table 74, page 45
Each individual device may have up to 2¹⁶ (65,536)
registers. The ISL35822 implements all the defined registers
for 10GBASE PMA/PMD, 10GBASE-X PCS and PHY XS
devices, and a few Vendor Specific registers for each
DEVAD respectively. The latter have been placed in the
blocks beginning at D.C000’h so as to avoid the areas
currently defined as for use by the XENPAK module and
similar MSA devices, to facilitate use of the ISL35822 in
such modules and systems.
Table 3. MDIO MANAGEMENT FRAME FORMATS
CLAUSE 22 FORMAT (FROM TABLE 22-10 IN IEEE STD 802.3-2002 EDITION, FOR REFERENCE)
OPERN
PRE
ST OP
PHYAD
REGAD
TA
DATA
IDLE
Read
1….1
01 10
PPPPP
RRRRR
Z0
DDDDDDDDDDDDDDDD
Z
Write
1….1
01 01
PPPPP
RRRRR
10
DDDDDDDDDDDDDDDD
Z
OPERN
PRE⁽¹⁾
CLAUSE 45 FORMAT (FROM TABLE 45-64 IN IEEE 802.3.ae-2002)
ST OP
PRTAD
DEVAD
TA
ADDRESS/DATA
IDLE
Addrs
1….1
00 00
PPPPP
DDDDD
10
AAAAAAAAAAAAAAAA
Z
Write
1….1
00 01
PPPPP
DDDDD
10
DDDDDDDDDDDDDDDD
Z⁽²⁾
Read
1….1
00 11
PPPPP
DDDDD
Z0
DDDDDDDDDDDDDDDD
Z
Read Inc
1….1
00 10
PPPPP
DDDDD
Z0
DDDDDDDDDDDDDDDD
Z
Note (1): The ‘Preamble’ consists of at least 32 bits. After a software reset, a few extra preamble bits may be needed, depending on the MDC clock rate. See timing
diagrams in Figure 15 and Figure 17.
Note (2): The actual register will not be updated until up to three additional MDC cycles have been received. See Figure 15.
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