14 minimum grant register, 15 maximum latency register – Texas Instruments Dual/Single Socket CardBus and UntraMedia Controller PCI7621 User Manual

Page 247

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11−9

11.14 Minimum Grant Register

The minimum grant register contains the minimum grant value for the flash media controller core.

Bit

7

6

5

4

3

2

1

0

Name

Minimum grant

Type

RU

RU

RU

RU

RU

RU

RU

RU

Default

0

0

0

0

0

1

1

1

Register:

Minimum grant

Offset:

3Eh

Type:

Read/Update

Default:

07h

Table 11−9. Minimum Grant Register Description

BIT

FIELD NAME

TYPE

DESCRIPTION

7−0

MIN_GNT

RU

Minimum grant. The contents of this field may be used by host BIOS to assign a latency timer register value
to the flash media controller. The default for this register indicates that the flash media controller may need
to sustain burst transfers for nearly 64

µ

s and thus request a large value be programmed in bits 15−8 of

the PCI7x21/PCI7x11 latency timer and class cache line size register at offset 0Ch in the PCI configuration
space (see Section 11.6).

11.15 Maximum Latency Register

The maximum latency register contains the maximum latency value for the flash media controller core.

Bit

7

6

5

4

3

2

1

0

Name

Maximum latency

Type

RU

RU

RU

RU

RU

RU

RU

RU

Default

0

0

0

0

0

1

0

0

Register:

Maximum latency

Offset:

3Eh

Type:

Read/Update

Default:

04h

Table 11−10. Maximum Latency Register Description

BIT

FIELD NAME

TYPE

DESCRIPTION

7−0

MAX_LAT

RU

Maximum latency. The contents of this field may be used by host BIOS to assign an arbitration priority level
to the flash media controller. The default for this register indicates that the flash media controller may need
to access the PCI bus as often as every 0.25

µ

s; thus, an extremely high priority level is requested. The

contents of this field may also be loaded through the serial EEPROM.

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