RTL8019AS datasheet(32/50 Pages) ETC1

32 / 50 page

8019AS.doc

2001-05-10

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SPECIFICATION

RTL8019AS

At the end of this process, one card remains. This card is assigned a handle referred to as the Card

Select Number (CSN) that will be used later to select the card. Cards which have been assigned a

CSN will not participate in subsequent iterations of the isolation protocol. Cards must be assigned a

CSN before they will respond to the other PnP commands.

It should be noted that the protocol permits the 8-bit checksum to be stored in non-volatile memory

on the card or generated by the on-card logic in real-time. The checksum algorithm is implemented

as a Linear Feedback Shift Register (LFSR), which is shown in Figure 3.

Vendor ID/

Serial number

Read of Serial

Isolation register

Reset values

Shift out

Figure 3. Checksum LFSR

The LFSR resets to 6AH upon receiving the Wake[CSN] command. The next shift value for the

LFSR is calculated as LFSR[1] XOR LFSR[0] XOR Serial Data. The LFSR is shifted right one bit

at the conclusion of each pair of reads to the Serial Isolation register. LFSR[7] is assigned the next

shift value described above.

After the first 64 pairs of reads of the Serial Isolation register, the LFSR will have the value of

serial identifier checksum.

Plug and Play cards must not drive the IOCHRDY signal during serial isolation. However, cards

may drive IOCHRDY at any other time.

Software Protocol

The Plug and Play software sends the initiation key to all Plug and Play cards to place them into

configuration mode. The software is then ready to perform the isolation protocol.

The Plug and Play software generates 72 pairs of I/O read cycles from the READ_DATA port. The

software checks the data returned from each pair of I/O reads for the 55H or AAH driven by the

hardware. If both 55H or AAH are read back, then the software assumes that the hardware had a

"1" bit in that position. All other results are assumed to be a "0".

During the first 64 bits, software generates a checksum using the received data. The checksum is

compared with the checksum read back in the last 8 bits of the sequence.

RTL8019AS датащи(PDF) 32 Page - List of Unclassifed Manufacturers