83C795 Datasheet, PDF (73/136 Pages) List of Unclassifed Manufacturers – Ethernet System Controller

83C795
HOST INTERFACE SECTION
regis ter map shown in Table 6-7 changes when the
adapter is run in I/O-mapped mode (s ee s ection
6.8.6). Als o, when the R OM s pace is dis abled
(when BIO.4 and BIO.5 are both s et), the R OM
configuration regis ters become read-only and
always read zeros .
T here are 22-bits of information in the P nP
configuration regis ters that are us edfor configuring
the 83C795. T hese bits are s hifted from the PnP
s ection to the 83C795 section whenever the chipis
activated. T he s ame bits are s hifted from the
83C795 s ection back to the PnP s ection at the end
of the initial E E R OM load (to get the default values
into the PnP regis ters ). S ome of thes e bits may
have to be remapped before they are s hifted so as
to match the formats of the two different regis ter
ISA ADDRESS SPACE
Address
Function
0x0279 ADDRESS
0x0A79 WRITE_DATA
0x0200 -
0x03FF
READ_DATA
PNP SECONDARY ADDRESS SPACE
Secondary
Address
Name
00
READ_DATA PORT ADDRESS
01
SERIAL ISOLATION
02
CONFIGURATION CONTROL
03
WAKE (CSN)
04
RESOURCE DATA
05
STATUS
06
CARD SELECT NUMBER
(CSN)
07
LOGICAL DEVICE NUMBER
30
ACTIVATE
31
I/O RANGE CHECK
40
RAM BASE ADDRESS [23-16]
41
RAM BASE ADDRESS [15-08]
42
RAM CONTROL
43
RAM RANGE LENGTH [23-16]
44
RAM RANGE LENGTH [15-08]
48
ROM BASE ADDRESS [23-16]
49
ROM BASE ADDRESS [15-08]
4A
ROM CONTROL
4B
ROM RANGE LENGTH [23-16]
4C
ROM RANGE LENGTH [15-08]
60
I/O BASE ADDRESS [15-08]
61
I/O BASE ADDRESS [07-00]
70
IRQ NUMBER
71
IRQ TYPE
EEROM CONTENTS
Resource String
Number
Item
0-7
8
Serial ID
Checksum
9-N
Resource Data
N+1
N+2
End Tag
Checksum
FIGURE 6-8. PLUG AND PLAY CONFIGURATION REGISTERS
60