Table 19. Signal Description Table (Continued)
Description
Signal
Type
RTS
O
Request To Send indicates to the external DCE that the internal serial port controller is ready
to send data.
SIN
I
Serial Data In receives the serial data from the external serial device or DCE into the internal
serial port controller.
SOUT
O
Serial Data Out transmits the serial data from the internal serial port controller to the external
serial device or DCE.
Keyboard Interfaces
KBD_COL7–
KBD_COL0
O
Matrix-Scanned Keyboard Column Outputs drive the matrix keyboard column lines.
(Open Collector Output with programmable termination)
KBD_ROW14–
KBD_ROW0
STI
I/O
I/O
Matrix-Scanned Keyboard Row Inputs samples the row lines on the matrix keyboard.
XT_CLK
XT Keyboard Clock is the clock signal for an external XT keyboard interface.
(Open Collector Output)
XT_DATA
XT Keyboard Data is the data signal for an external XT keyboard interface.
(Open Collector Output)
General-Purpose Input/Output
GPIO31–GPIO15
GPIO_CS14–
GPIO_CS0
B
General Purpose I/Os and Programmable Chip Selects
Each of the GPIOs can be programmed to be an input or an output.
As outputs, all of the GPIOs can be programmed to be High or Low. Some of the GPIOs can
be programmed to be High or Low for each of the power management modes. Also as
outputs, some of these pins can be individually programmed as chip selects for other
external peripheral devices. These can be configured as direct memory address decodes or
I/O decodes qualified or non-qualified by the ISA bus command signals. Any one of the
GPIO_CSx signals can be configured as ROMCS2.
As inputs, all the GPIOs can be read back with a register bit. Some of these pins can be
individually programmed to act as activity triggers, wake-up sources, or SMIs.
Serial Infrared Port
SIRIN
I
Infrared Serial Input is the digital input for the serial infrared interface.
Infrared Serial Output is the digital output for the serial infrared interface.
SIROUT
O
PC Card Controller (ÉlanSC400 Microcontroller Only)
(Note: The names in parentheses in this section are those used in PC Card Memory and I/O mode.)
BVD1_A
(STSCHG_A)–
BVD1_B
I
Battery Voltage Detect is driven Low by a PC Card when its on-board battery is dead. When
the PC Card interface is configured for I/O, this signal can be driven by the card to indicate
a card status change. It is typically used to generate a system IRQ in this mode. These
signals are not supported on the ÉlanSC410 microcontroller.
(STSCHG_B)
BVD2_A (SPKR_A)
(DRQ_A)–
BVD2_B (SPKR_B)
(DRQ_B)
I
Battery Voltage Detect is driven Low by a PC Card when its on-board battery is weak. When
the PC Card interface is configured for I/O, this signal can be driven by the card’s speaker
output. When enabled, this signal can drive the chip SPKR output. When PC Card DMA is
enabled, the DMA request from the PC Card can be programmed to appear on this signal.
See also the description for WP_A (IOIS16_A) (DRQ_A) and WP_B (IOIS16_B) (DRQ_B);
the DMA request can also be programmed to appear on these pins. These signals are not
supported on the ÉlanSC410 microcontroller.
CD_A–CD_B
CD_A2
I
Card Detect indicates that the card is properly inserted. Socket A is capable of being
configured to use two card detect inputs and Socket B is only provided with one. If only one
card detect is to be used for a socket, the input signals should be driven from a logical AND
(digital OR) of the CD1 and CD2 signals from their respective card interfaces. These signals
are not supported on the ÉlanSC410 microcontroller.
Élan™SC400 and ÉlanSC410 Microcontrollers Data Sheet
67
AMD [ AMD ]
