LAN9353 Datasheet, PDF (240/523 Pages) Microchip Technology – Interfaces at up to 200Mbps via Turbo MII

LAN9353
Bits
Description
28 Auto Decrement (AUTO_DEC)
This bit enables/disables the auto decrement feature.
When this bit is set, a write to the Switch Fabric CSR Interface Data Register
(SWITCH_CSR_DATA) will automatically set the CSR Busy (CSR_BUSY)
bit. Once the write command is finished, the CSR Address
(CSR_ADDR[15:0]) will automatically decrement.
When this bit is set, a read from the Switch Fabric CSR Interface Data Regis-
ter (SWITCH_CSR_DATA) will automatically decrement the CSR Address
(CSR_ADDR[15:0]) and set the CSR Busy (CSR_BUSY) bit. This bit should
be cleared by software before the last read from the SWITCH_CSR_DATA
register.
27:20
19:16
0: Disable Auto Decrement
1: Enable Auto Decrement
RESERVED
CSR Byte Enable (CSR_BE[3:0])
This field is a 4-bit byte enable used for selection of valid bytes during write
operations. Bytes which are not selected will not be written to the corre-
sponding Switch Fabric CSR.
CSR_BE[3] corresponds to register data bits [31:24]
CSR_BE[2] corresponds to register data bits [23:16]
CSR_BE[1] corresponds to register data bits [15:8]
CSR_BE[0] corresponds to register data bits [7:0]
Typically all four-byte-enables should be set for auto increment and auto dec-
rement operations.
15:0 CSR Address (CSR_ADDR[15:0])
This field selects the 16-bit address of the Switch Fabric CSR that will be
accessed with a read or write operation. Refer to Table 10-9, “Indirectly
Accessible Switch Control and Status Registers,” on page 246 for a list of
Switch Fabric CSR addresses.
Type
R/W
RO
R/W
R/W
Default
0b
-
0h
00h
DS00001925A-page 240
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