LAN83C175 Datasheet, PDF (64/92 Pages) SMSC Corporation – Ethernet CARDBUS Integrated Controller With Modem Support

Modem and External Flash RAM Interface and Control
Access to the external modem is made
through accesses by the host to the EPIC/C.
The CardBus configuration space for the
modem function must be setup during card
initialization. Once this is done, I/O or
memory space writes or reads on the CardBus
to these defined spaces will be passed to the
modem or its register space. Accesses to the
modem I/O address space are defined in
Table 3, with dword addresses shown. Note
that accesses to the physical modem read and
write addresses physically found in the
modem, such as the transmit and receive
FIFO’s. The other registers are physically
located in the EPIC/C.
I/O accesses to dword addresses 00-7C are
passed to the modem itself on a byte addressed
basis. For example, if a read access has the I/O
base address register, with bit CAD(7) equal to ‘0’,
bits CAD(6:0) are passed directly to the modem.
A modem, typically, will only use 3-6 address
lines, but the EPIC/C can accommodate up to 128
byte addresses to the physical modem in the
EPIC/C’s I/O space.
Accesses to dword addresses 80-94 will return the
registers shown in Table and defined later in the
document.
Access to the external RAM is through the 64K
byte configuration space defined in the Expansion
ROM Base Address.
Modem Registers Map
Table 4 - Modem I/O Address Space
00
40
80 NVCTL_m
C0
04
44
84 STATUS_m
C4
08
48
88 FEVTR
C8
0C
4C
8C FEVTRMSKR CC
10
50
90 FPRSTSTR
D0
14
54
94 FFRCEVTR
D4
18
Physical
58
Physical
98
D8
1C
Modem
5C
Modem
9C
DC
20
Address
60
Address
A0
E0
24
Space
64
Space
A4
E4
28
(must be
68
(must be
A8
Unused
E8
2C byte addressed) 6C
byte
AC
EC
addressed)
30
70
B0
F0
34
74
B4
F4
38
78
B8
F8
3C
7C
BC
FC
Unused
64