Texas Instruments PCI7421, PCI7411, PCI7611, PCI7621 manual Aoe

Table 2−11. 16-Bit PC Card Interface Control Terminals (Continued)

SKT A TERMINAL

SKT B TERMINAL†

DESCRIPTION

I/O

POWER

NAME

NO.

NAME

NO.

TYPE

RAIL

Output enable.

is driven low by the controller to enable 16-bit memory PC Card

OE

data output during host memory read cycles.

VCCA/

A_OE

C12

B_OE

L18

DMA terminal count. OE is used as terminal count (TC) during DMA operations to a

O

VCCB

16-bit PC Card that supports DMA. The controller asserts OE to indicate TC for a DMA

write operation.

Ready. The ready function is provided when the 16-bit PC Card and the host socket are

configured for the memory-only interface. READY is driven low by 16-bit memory PC

Cards to indicate that the memory card circuits are busy processing a previous write

A_READY

C04

B_READY

B19

command. READY is driven high when the 16-bit memory PC Card is ready to accept a

I

VCCA/

(IREQ)

(IREQ)

new data transfer command.

VCCB

Interrupt request.

IREQ

is asserted by a 16-bit I/O PC Card to indicate to the host that a

controller on the 16-bit I/O PC Card requires service by the host software. IREQ is high

(deasserted) when no interrupt is requested.

Attribute memory select.

remains high for all common memory accesses. When

REG

REG is asserted, access is limited to attribute memory (OE or WE active) and to the I/O

space (IORD or IOWR active). Attribute memory is a separately accessed section of

card memory and is generally used to record card capacity and other configuration and

VCCA/

A_REG

C05

B_REG

F15

attribute information.

O

VCCB

DMA acknowledge. REG is used as a DMA acknowledge (DACK) during DMA

operations to a 16-bit PC Card that supports DMA. The controller asserts REG to

indicate a DMA operation. REG is used in conjunction with the DMA read (IOWR) or

DMA write (IORD) strobes to transfer data.

A_RESET

A06

B_RESET

F17

PC Card reset. RESET forces a hard reset to a 16-bit PC Card.

O

VCCA/

VCCB

A03

C18

Voltage sense 1 and voltage sense 2.

and

when used in conjunction with

VCCA/

A_VS1

B_VS1

VS1

VS2,

I/O

A_VS2

E08

B_VS2

F19

each other, determine the operating voltage of the PC Card.

VCCB

Bus cycle wait.

is driven by a 16-bit PC Card to extend the completion of the

VCCA/

B03

B18

WAIT

I

A_WAIT

B_WAIT

memory or I/O cycle in progress.

VCCB

Write enable.

is used to strobe memory write data into 16-bit memory PC Cards.

WE

WE is also used for memory PC Cards that employ programmable memory

technologies.

VCCA/

A_WE

B09

B_WE

J15

O

DMA terminal count. WE is used as a TC during DMA operations to a 16-bit PC Card

VCCB

that supports DMA. The controller asserts WE to indicate the TC for a DMA read

operation.

Write protect. WP applies to 16-bit memory PC Cards. WP reflects the status of the

write-protect switch on 16-bit memory PC Cards. For 16-bit I/O cards, WP is used for

the 16-bit port (IOIS16) function.

is asserted by the 16-bit

A_WP

B_WP

I/O is 16 bits.

IOIS16

applies to 16-bit I/O PC Cards.

IOIS16

VCCA/

C03

A18

PC Card when the address on the bus corresponds to an address to which the 16-bit

I

(IOIS16)

(IOIS16)

VCCB

PC Card responds, and the I/O port that is addressed is capable of 16-bit accesses.

DMA request. WP can be used as the DMA request signal during DMA operations to a

16-bit PC Card that supports DMA. If used, then the PC Card asserts WP to indicate a

request for a DMA operation.

†These terminals are reserved for the PCI7611 and PCI7411 controllers.

2−21