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AMD Geode™ SC1200/SC1201 Processor Data Book 97
SuperI/O Module
32579B
5.4.1 SIO Control and Configuration Registers
Table 5-4 lists the SIO Control and Configuration registers and Table 5-5 provides their bit formats.
Table 5-4. SIO Control and Configuration Register Map
Index Type Name Power Rail Reset Value
20h RO SID. SIO ID V
CORE
F5h
21h R/W SIOCF1. SIO Configuration 1 V
CORE
01h
22h R/W SIOCF2. SIO Configuration 2 V
PP
02h
27h RO SRID. SIO Revision ID V
CORE
01h
2Eh --- RSVD. Reserved exclusively for AMD use. --- ---
Table 5-5. SIO Control and Configuration Registers
Bit Description
Index 20h SIO ID Register - SID (RO) Reset Value: F5h
7:0 Chip ID. Contains the identity number of the module. The SIO module is identified by the value F5h.
Index 21h SIO Configuration 1 Register - SIOCF1 (RW) Reset Value: 01h
7:6 General Purpose Scratch. When bit 5 is set to 1, these bits are RO. After reset, these bits can be read or write. Once
changed to RO, the bits can be changed back to R/W only by a hardware reset.
5 Lock Scratch. This bit controls bits 7 and 6 of this register. Once this bit is set to 1 by software, it can be cleared to 0 only
by a hardware reset.
0: Bits 7 and 6 of this register are R/W bits. (Default)
1: Bits 7 and 6 of this register are RO bits.
4:2 Reserved.
1 SW Reset. Read always returns 0.
0: Ignored. (Default)
1: Resets all devices that are reset by MR (with the exception of the lock bits) and the registers of the SWC.
0 Global Device Enable. This bit controls the function enable of all the logical devices in the SIO module, except the SWC
and the RTC. It allows them to be disabled simultaneously by writing to a single bit.
0: All logical devices in the SIO module are disabled, except the SWC and the RTC.
1: Each logical device is enabled according to its Activate register at Index 30h. (Default)
Index 22h SIO Configuration 2 Register - SIOCF2 (R/W) Reset Value: 02h
Note: This register is reset only when V
PP
is first applied.
7 Reserved.
6:4 General Purpose Scratch. Battery-backed.
3:2 Reserved.
1 Reserved.
0 Reserved. (RO)
Index 27h SIO Revision ID Register - SRID (RO) Reset Value: 01h
7:0 SIO Revision ID. (RO) This RO register contains the identity number of the chip revision. SRID is incremented on each revi-
sion.