cs5535 National Semiconductor Corporation, cs5535 Datasheet - Page 436

• Manufacturer Part Number: cs5535
• Description: Geode Cs5535 Companion Multi-function South Bridge
• Manufacturer: National Semiconductor Corporation

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GPIO Subsystem Register Descriptions
5.16.1 Atomic Bit Programming Model
The registers in Section 5.16.2 "GPIO Low/High Bank Feature Bit Registers", starting on page 438, that are referred to as
“atomic” all follow the same programming model (i.e., work exactly the same way) but each controls a different GPIO fea-
ture. Two data bits are used to control each GPIO Feature bit, each pair of bits operate in an exclusive-OR pattern. Refer to
Section 4.15.2 "Register Strategy" on page 148 for further details.
The Low Bank registers control programming of GPIO15 through GPIO0 and the High Bank registers program GPIO31
through GPIO16. The tables that follow provide the register/bit formats for the Low and High Bank GPIO feature configura-
tion registers.
Note: All register bits dealing with GPIO31, GPIO30, GPIO29 and GPIO23 are Reserved .
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
31,15
30,14
29,13
28,12
27,11
26,10
25,9
24,8
23,7
22,6
21,5
20,4
19,3
18,2
17,1
16,0
Bit
Name
GPIO15
GPIO14
GPIO13
GPIO12
GPIO11
GPIO10
GPIO9
GPIO8
GPIO7
GPIO6
GPIO5
GPIO4
GPIO3
GPIO2
GPIO1
GPIO0
Table 5-61. Low Bank Atomic Bit Descriptions
Description
GPIO15 Feature.
00: No change.
01: Feature bit = 1.
10: Feature bit = 0.
11: No change.
GPIO14 Feature. See bits [31,15] for decode.
GPIO13 Feature. See bits [31,15] for decode.
GPIO12 Feature. See bits [31,15] for decode.
GPIO11 Feature. See bits [31,15] for decode.
GPIO10 Feature. See bits [31,15] for decode.
GPIO9 Feature. See bits [31,15] for decode.
GPIO8 Feature. See bits [31,15] for decode.
GPIO7 Feature. See bits [31,15] for decode.
GPIO6 Feature. See bits [31,15] for decode.
GPIO5 Feature. See bits [31,15] for decode.
GPIO4 Feature. See bits [31,15] for decode.
GPIO3 Feature. See bits [31,15] for decode.
GPIO2 Feature. See bits [31,15] for decode.
GPIO1 Feature. See bits [31,15] for decode.
GPIO0 Feature. See bits [31,15] for decode.
Table 5-60. Low Bank Atomic Register Map
(Continued)
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