Notes:
1. The shared GPIO_CS12–GPIO_CS5 and ISA signals:
As GPIO_CS signals, they are active in Suspend mode: that is, if they are inputs before Suspend, they are still inputs during
Suspend (they can be used to wake up the system); if they are outputs before Suspend, they are still outputs during Suspend
(they can be programmed to change state by mode). As inputs, the pullup or pulldown on the signal can be disabled; if
disabled, it is disabled in all modes. When the signal is an output, the built-in resistors are automatically disabled.
The ISA function for each pin is programmable by functional group: that is, the system can choose to use PIRQ0 and still use
the DMA pins as GPIO_CSxs (the pin multiplexing options are explained elsewhere in this document). As ISA signals, these
pins are programmable to support a system with ISA peripherals powered up or down in Suspend mode (Power-Down Group
C). For those signals that are High when deasserted, there is an option to three-state them with no built-in resistors, so an
external resistor can be placed on the board to pull them up to 5 V.
Summary: GPIO_CS12: Built-in pulldown resistor that is invoked by:
–Reset
–ISA signal enabled on this pin (the pin will be PDRQ0).
–The pulldown is disabled by this pin being a GPIO_CS and an output.
–The pulldown can be programmed to be disabled when the pin is a GPIO_CS input.
Summary: GPIO_CS11: Built-in pullup and pulldown resistors that are invoked by:
–Reset invokes the pullup.
–When enabled as the ISA signal PDACK0:
•In normal operation, this signal is an output and no pullup or pulldown is needed.
•The pulldown is invoked by Suspend mode and the ISA bus is programmed to be powered off in Suspend (Power-
Down Group C).
•If the ISA bus is programmed for 5-V use and is not powered down in Suspend, then this signal is three-state without
a built-in pullup or pulldown resistor.
–When enabled as the GPIO_CS11 signal:
•As an output, the pullup and pulldown are disabled in all modes, and these GPIO_CSx signals can be active in
Suspend.
•As an input, the pullup can be programmed to be enabled or disabled; this will then be the state of the pin in all
modes, including Suspend.
Summary: GPIO_CS10–GPIO_CS9: Built-in pullup and pulldown resistors that are invoked by:
–Reset invokes the pullups.
–When enabled as the ISA signals AEN and TC:
•In normal operation, these signals are outputs and no pullup or pulldown is needed.
•The pulldowns are invoked by Suspend mode.
–When enabled as the GPIO_CS10–GPIO_CS9 signals:
•As an output, the pullup and pulldown are disabled in all modes, and these GPIO_CS signals can be active in Suspend.
•As an input, the pullup can be programmed to be enabled or disabled; this will then be the state of the pin in all
modes, including Suspend.
Summary: GPIO_CS8–GPIO_CS5: Built-in pullup and pulldown resistors that are invoked by:
–Reset invokes the pullups.
–When enabled as PIRQ1–PIRQ0, IOCHRDY, and IOCS16:
•In normal operation and Suspend, these signals are inputs and the pullup resistors are active.
•The pulldowns are invoked by Suspend mode and the ISA bus interface programmed for power off in Suspend
(Power-Down Group C).
–When enabled as the GPIO_CS8–GPIO_CS5 signals:
•As an output, the pullup and pulldown are disabled in all modes, and these GPIO_CSx signals can be active in
Suspend.
•As an input, the pullup can be programmed to be enabled or disabled; this will then be the state of the pin in all
modes, including Suspend.
50
Élan™SC400 and ÉlanSC410 Microcontrollers Data Sheet
AMD [ AMD ]
