CS8900A
Crystal LAN™ Ethernet Controller
Word Address
FIRST WORD in DATA BLOCK
00h A120h
Value
Description
Configuration Block Header.
The high byte, A1h, indicates a ‘C46 EEPROM is attached. The Link Byte,
20h, indicates the number of bytes to be used in this block of configuration
data.
FIRST GROUP of WORDS
01h
2020h
Group Header for first group of words.
Three words to be loaded, beginning at 0020h in PacketPage memory.
02h
03h
04h
0300h
0003h
0001h
I/O Base Address
Interrupt Number
DMA Channel Number
SECOND GROUP of WORDS
05h
502Ch
Group Header for second group of words.
Six words to be loaded, beginning at 002Ch in PacketPage memory.
06h
07h
08h
09h
0Ah
0Bh
E000h
000Fh
0000h
000Dh
C000h
000Fh
Memory Base Address - low word
Memory Base Address - high word
Boot PROM Base Address - low word
Boot PROM Base Address - high word
Boot PROM Address Mask - low word
Boot PROM Address Mask - high word
THIRD GROUP of WORDS
0Ch
2158h
Group Header for third group of words.
Three words to be loaded, beginning at 0158 in PacketPage memory.
0Dh
0010h
0000h
0000h
Individual Address - Octet 0 and 1
Individual Address - Octet 2 and 3
Individual Address - Octet 4 and 5
0Eh
0Fh
CHECKSUM Value
10h
2800h
The high byte, 28h, is the Checksum Value. In this example, the checksum
includes word addresses 00h through 0Fh. The hexadecimal sum of the
bytes is D8h, resulting in a 2’s complement of 28h. The low byte, 00h, pro-
vides a pad to the word boundary.
* FFFFh is a special code indicating that there are no more words in the EEPROM.
Table 7. EEPROM Configuration Block Example
the EEPROM). Address space 80h to AFh is
reserved.
ending with the checksum. Each group of con-
figuration data is used to program a Pack-
etPage register (or set of PacketPage
registers in some cases) with an initial non-de-
fault value.
3.4.3.1 Reset Configuration Block Structure
The Reset Configuration Block is a block of
contiguous 16-bit words starting at EEPROM
address 00h. It can be divided into three logi-
cal sections: a header, one or more groups of
configuration data words, and a checksum val-
3.4.3.2 Reset Configuration Block Header
The header (first word of the block located at
EEPROM address 00h) specifies the type of
ue. All of the words in the Reset Configuration EEPROM used, whether or not a Reset Con-
Block are read sequentially by the CS8900A figuration block is present, and if so, how many
after each reset, starting with the header and
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