LAN9353 Datasheet, PDF (230/523 Pages) Microchip Technology – Interfaces at up to 200Mbps via Turbo MII

LAN9353
Switch Fabric CSR Interface Command Register (SWITCH_CSR_CMD) is incremented or decremented accordingly
and another read cycle is started automatically. The user should clear the Auto Increment (AUTO_INC) and Auto Dec-
rement (AUTO_DEC) bits before reading the last data to avoid an unintended read cycle.
Figure 10-9 illustrates the process required to perform a Switch Fabric CSR read. The minimum wait periods as speci-
fied in Table 5-2, “Read After Write Timing Rules,” on page 47 and Table 5-3, “Read After Read Timing Rules,” on
page 49 are required where noted.
FIGURE 10-9:
SWITCH FABRICS CSR READ ACCESS FLOW DIAGRAM
CSR Read
Idle
CSR Read Auto
Increment /
Decrement
Idle
Write
Command
Register
min wait period
Read
Command
Register
CSR_BUSY = 1
CSR_BUSY = 0
Write
Command
Register
min wait period
min wait period
Read
Command
Register
CSR_BUSY = 1
CSR_BUSY = 0
Read Data
Register
last _No
data?
Read Data
Register
Yes
Write
Command
Register
Read Data
Register
DS00001925A-page 230
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