CS8920 查看數據表（PDF） - Cirrus Logic
零件编号
产品描述 (功能)
生产厂家
CS8920 Datasheet PDF : 66 Pages
| |||
CS8920 Technical Reference Manual
3.0 EEPROM-based Configuration
The CS8920 and media access control
(MAC) driver obtain configuration data
from a serial EEPROM connected via the
CS8920’s serial interface. This eliminates
the need for configuration jumpers or
switches on the ISA adapter or
motherboard.
3.1 Format of Configuration Data
Three types of configuration data are stored
in the EEPROM: configuration data
automatically loaded into the CS8920 after
each reset, configuration data used by the
MAC driver, and Plug and Play (PnP)
resource data.
00h
to
Reset Configuration Block
1Bh
1Ch
to
Driver Configuration Block
34h
35h
to
PnP Resource Data
7Fh
Figure 3.1 EEPROM Data Blocks
Each type of configuration data is grouped
together, organized as 16-bit words, in a
AN84REV1
separate block of the EEPROM. The
arrangement and location of the three
blocks of configuration data are shown in
Figure 3.1.
3.2 Reset Configuration Block
After each reset (except EEPROM reset)
the CS8920 checks to see if an EEPROM is
connected. If an EEPROM is present, the
CS8920 automatically loads first block of
data stored in the EEPROM into its internal
registers. This block of data is referred to
as the Reset Configuration Block. It is
used to initialize the CS8920 after each
reset. If an EEPROM is not present (or a
checksum error indicates the Reset
Configuration Block is invalid) the CS8920
executes an EEPROM reset causing all
PacketPage registers to be loaded with their
default values.
Note: The default state of the CS8920
after an EEPROM reset is inactive (i.e., all
normal ISA bus IO to or from the CS8920
is disabled). Communication with the
CS8920 must then be established using the
Crystal auxiliary key written to the CS8920
via the PnP write-data port. Refer to
Section 3.5 for more information on using
the CS8920 auxiliary key and its use in
programming and initializing the
EEPROM.
3.2.1 Reset Configuration Block Format
The Reset Configuration Block must begin
at EEPROM word address 0x00 and can
vary in length up to a maximum of 28
words (word address 0x1B).
36
Share Link: 