CS5530A Datasheet, PDF (80/259 Pages) National Semiconductor (TI) – Geode CS5530A I/O Companion Multi-Function South Bridge

Revision 1.1
Power Management
4.4.3.4 General Purpose I/O Pins
The CS5530A provides up to eight GPIO (general purpose
I/O) pins. Five of the pins (GPIO[7:4] and GPIO1) have
alternate functions. Table 4-31 shows the bits used for
GPIO pin function selection.
Each GPIO pin can be configured as an input or output.
GPIO[7:0] can be independently configured to act as edge-
sensitive SMI events. Each pin can be enabled and config-
ured to be either positive-edge sensitive or negative-edge
sensitive. These pins then cause an SMI to be generated
when an appropriate edge condition is detected. The
power management status registers indicate that a GPIO
external SMI event has occurred.
The GPIO Pin Direction Register 1 (F0 Index 90h) selects
whether the GPIO pin is an input or output. The GPIO Pin
Data Register 1 (F0 Index 91h) contains the direct values
of the GPIO pins. Write operations are valid only for bits
defined as outputs. Reads from this register read the last
written value if the pin is an output.
GPIO Control Register 1 (F0 Index 92h) configures the
operation of the GPIO pins for their various alternate func-
tions. Bits [5:3] set the edge sensitivity for generating an
SMI on the GPIO[2:0] (input) pins respectively. Bits [2:0]
enable the generation of an SMI. Bit 6 enables GPIO6 to
act as the lid switch input. Bit 7 determines which edge
transition will cause General Purpose Timer 2 (F0 Index
8Ah) to reload.
Table 4-32 shows the bit formats for the GPIO pin configu-
ration and control registers.
Table 4-31. GPIO Pin Function Selection
Bit Description
F0 Index 43h
USB Shadow Register (R/W)
Reset Value = 03h
6
Enable SA20: Pin AD22 configuration: 0 = GPIO4; 1 = SA20. If F0 Index 43h bit 6 or bit 2 is set to 1, then pin AD22 = SA20.
2
Enable SA[23:20]: Pins AF23, AE23, AC21, and AD22 configuration: 0 = GPIO[7:4]; 1 = SA[23:20]. If F0 Index 43h bit 6 or
bit 2 is set to 1, then pin AD22 = SA20.
F3BAR+Memory Offset 08h-0Bh
Codec Status Register (R/W)
Reset Value = 00000000h
21
Enable SDATA_IN2: Pin AE24 functions as: 0 = GPIO1; 1 = SDATA_IN2.
For this pin to function as SDATA_IN2, it must first be configured as an input (F0 Index 90h[1] = 0).
Table 4-32. GPIO Pin Configuration/Control Registers
Bit Description
F0 Index 90h
GPIO Pin Direction Register 1 (R/W)
Reset Value = 00h
7
GPIO7 Direction: Selects if GPIO7 is an input or output: 0 = Input; 1 = Output.
6
GPIO6 Direction: Selects if GPIO6 is an input or output: 0 = Input; 1 = Output.
5
GPIO5 Direction: Selects if GPIO5 is an input or output: 0 = Input; 1 = Output.
4
GPIO4 Direction: Selects if GPIO4 is an input or output: 0 = Input; 1 = Output.
3
GPIO3 Direction: Selects if GPIO3 is an input or output: 0 = Input; 1 = Output.
2
GPIO2 Direction: Selects if GPIO2 is an input or output: 0 = Input; 1 = Output.
1
GPIO1 Direction: Selects if GPIO1 is an input or output: 0 = Input; 1 = Output.
0
GPIO0 Direction: Selects if GPIO0 is an input or output: 0 = Input; 1 = Output.
Note: Several of these pins have specific alternate functions. The direction configured here must be consistent with the pins’ use as the
alternate function.
F0 Index 91h
GPIO Pin Data Register 1 (R/W)
Reset Value = 00h
7
GPIO7 Data: Reflects the level of GPIO7: 0 = Low; 1 = High.
6
GPIO6 Data: Reflects the level of GPIO6: 0 = Low; 1 = High.
5
GPIO5 Data: Reflects the level of GPIO5: 0 = Low; 1 = High.
4
GPIO4 Data: Reflects the level of GPIO4: 0 = Low; 1 = High.
3
GPIO3 Data: Reflects the level of GPIO3: 0 = Low; 1 = High.
2
GPIO2 Data: Reflects the level of GPIO2: 0 = Low; 1 = High.
1
GPIO1 Data: Reflects the level of GPIO1: 0 = Low; 1 = High.
0
GPIO0 Data: Reflects the level of GPIO0: 0 = Low; 1 = High.
Note: This register contains the direct values of GPIO[7:0] pins. Write operations are valid only for bits defined as output. Reads from
this register will read the last written value if the pin is an output. The pins are configured as inputs or outputs in F0 Index 90h.
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AMD Geode™ CS5530A Companion Device Data Book