DS3181/DS3182/DS3183/DS3184
85
8.3.5.4
POS-PHY Level 3 Functional Timing
Figure 8-38 shows a multiport transmit interface multiple packet transfer to different PHY ports. On clock edge 1,
PHY port 'N' indicates to the POS device that it can accept a block of packet data by asserting TPXA. On clock
edge 3, the POS device selects PHY port 'N' by placing its address on TDATA and asserting TSX while
TEN is
deasserted. On clock edge 4, the POS device starts a packet transfer to PHY port 'N' by deasserting TSX,
asserting
TEN, placing the first byte of packet data on TDATA, and asserting TSOX to indicate the transfer of the
first byte of the packet. On clock edge 5, the POS device deasserts TSOX as it continues to place additional bytes
of the packet on TDATA and PHY port 'N' asserts TSPA. On clock edge 11, the POS device polls PHY port 'L'. On
clock edge 12, PHY port 'N' indicates that it cannot accept any more data transfers by deasserting TSPA. On clock
edge 13, PHY port 'L' indicates to the POS device that it can accept a block of packet data by asserting TPXA. On
clock edge 14, the POS device deasserts
TEN to end the packet transfer process to PHY port 'N' and selects PHY
port 'L' by placing its address on TDATA and asserting TSX while
TEN is deasserted. On clock edge 15, the POS
device starts a packet transfer to PHY port 'L' by asserting
TEN, deasserting TSX, placing the first byte of packet
data on TDATA, and asserting TSOX to indicate the transfer of the first byte of the packet. On clock edge 16, the
POS device deasserts TSOX as it continues to place additional bytes of the packet on TDATA and PHY port 'L'
asserts TSPA.
Figure 8-38. POS-PHY Level 3 Transmit Multiple Packet Transfer In-Band Addressing
M
N
O
L
P
P39
P38
PM
O
LN
P40
P41
P42
TCLK
TADR
TPXA
P
M
N
O
P
L
M
N
OP
L
N
1
19
20
23
4
5
7
6
8
10
11
12
13
14
15
16
17
18
9
X
P5
P6
X
TEN
TEOP
TERR
TDAT
Transfer
To PHY
N
LN
P
M
TSPA
OP
M
O
L
N
P43
TSOX
P44
L
P1
P2
P3
P4
TSX
M
O
…
M
L
N
…
N
P1
P2
…
P
L
Figure 8-39 shows a multiport receive-interface multiple packet transfer from different ports. On clock edge 1, the
POS device indicates to PHY port 'N' that it is ready to accept a block of packet data by asserting
REN. On clock
edge 3, the PHY device selects port 'N' for transfer by asserting RSX and placing its address on RDATA. On clock
edge 4, PHY port 'N' starts packet transfer by deasserting RSX, asserting RVAL, placing the first byte of the packet
on RDATA, and asserting RSOX to indicate that this is the first transfer of the packet. On clock edge 5, PHY port
'N' deasserts RSOX as it leaves RVAL asserted and continues to place additional bytes of the packet on RDATA.
On clock edge 10, PHY port 'N' places the last byte of the packet on RDATA, and asserts REOP to indicate that
this is the last transfer of the packet. On clock edge 11, the PHY device deasserts RVAL and REOP ending the
packet transfer process from port 'N' and selects PHY port 'L' for transfer by asserting RSX and placing its address
on RDATA. On clock edge 12, PHY port 'L' starts packet transfer by deasserting RSX, asserting RVAL, placing the
first byte of the packet on RDATA, and asserting RSOX to indicate that this is the first transfer of the packet. On
clock edge 13, PHY port 'L' deasserts RSOX as it leaves RVAL asserted and continues to place additional bytes of
the packet on RDATA.