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Revision 1.1
G
SuperI/O Module
(Continued)
4.3
This section describes the structure of the configuration
register file, and the method of accessing the configuration
registers.
CONFIGURATION STRUCTURE / ACCESS
4.3.1
The SIO configuration access is performed via an Index-
Data register pair, using only two system I/O byte locations.
The base address of this register pair is determined
according to the state of the IO_SIOCFG_IN bit field of the
Core Logic module (F5BAR0+I/O Offset 00h[26:25]). Table
4-1 shows the selected base addresses as a function of the
IO_SIOCFG_IN bit field.
Index-Data Register Pair
The Index register is an 8-bit R/W register located at the
selected base address (Base+0). It is used as a pointer to
the configuration register file, and holds the index of the
configuration register that is currently accessible via the
Data register. Reading the Index register returns the last
value written to it (or the default of 00h after reset).
The Data register is an 8-bit virtual register, used as a data
path to any configuration register. Accessing the data reg-
ister results with physically accessing the configuration reg-
ister that is currently pointed by the Index register.
4.3.2
Each functional block is associated with a Logical Device
Number (LDN). The configuration registers are grouped
into banks, where each bank holds the standard configura-
tion registers of the corresponding logical device. Table 4-2
shows the LDNs of the device functional blocks.
Banked Logical Device Registers
Figure 4-3 shows the structure of the standard PnP config-
uration register file. The SIO Control and Configuration reg-
isters are not banked and are accessed by the Index-Data
register pair only (as described above). However, the Logi-
cal Device Control and Configuration registers are dupli-
cated over four banks for four logical devices. Therefore,
accessing a specific register in a specific bank is performed
by two-dimensional indexing, where the LDN register
selects the bank (or logical device), and the Index register
selects the register within the bank. Accessing the Data
register while the Index register holds a value of 30h or
higher results in a physical access to the Logical Device
Configuration registers currently pointed to by the Index
register, within the logical device bank currently selected by
the LDN register.
Figure 4-3. Structure of the Standard
Configuration Register File
Table 4-1. SIO Configuration Options
IO_SIOCFG_IN
Settings
I/O Address
Description
Index
Register
Data
Register
00
-
-
SIO disabled
01
-
-
Configuration
access disabled
10
002Eh
002Fh
Base address 1
selected
11
015Ch
015Dh
Base address 2
selected
Table 4-2. LDN Assignments
LDN
Functional Block
00h
Real Time Clock (RTC)
01h
System Wakeup Control (SWC)
02h
Infrared Communication Port (IRCP)
05h
ACCESS.bus 1 (ACB1)
06h
ACCESS.bus 2 (ACB2)
08h
Serial Port
07h
20h
2Fh
30h
60h
63h
70h
71h
75h
FEh
Logical Device Number Register
SIO Configuration Registers
Logical Device Control Register
Standard Logical Device
Banks
(One per Logical Device)
F0h
Bank
Select
74h
Standard Registers
Special (Vendor-defined)
Logical Device
Configuration Registers