GL811USB datasheet(14/36 Pages) ETC

14 / 36 page

GL811USB – USB 2.0 to ATA / ATAPI Bridge Controller

Page 13

6.3.4 Switching Characteristics

Parameter

Min

Typ

Max

Unit

X1 crystal frequency

11.97

12.03

MHz

X1 cycle time

83.3

D+/D- rise time with 50pF loading

D+/D- fall time with 50pF loading

6.4 AC Characteristics- ATA/ ATAPI

The GL811USB complies with ATA / ATAPI-6 specification rev 1.0, which supports

following data transfer modes:

1. PIO (Programmed Input/ Output) data transfer:

PIO data transfers are performed by the host processor utilizing PIO register

accesses to the Data register.

2. DMA (Direct Memory Access) data transfer:

DMA data transfer means of data transfer between device and host memory

without host processor intervention.

- Multiword DMA: Multiword DMA is a data transfer protocol used with the READ

DMA, WRITE DMA, READ DMA QUEUED, WRITE DMA QUEUED and

PACKET commands. When a Multiword DMA transfer is enabled as indicated by

IDENTIFY DEVICE or IDENTIFY PACKET DEVICE data, this data transfer

protocol shall be used for the data transfers associated with these commends.

(Please refer to the ATA / ATAPI-6 specification rev 1.0 for more information.)

- Ultra DMA: Ultra DMA Is a data transfer protocol used with the READ DMA,

WRITE DMA, READ DMA QUEUED, WRITE DMA QUEUED and PACKET

commands. When this protocol is enabled, the Ultra DMA protocol shall be used

instead of the Multiword DMA protocol when these commands are issued by the

host. This protocol applies to the Ultra DMA data burst only. (Please refer to the

ATA / ATAPI-6 specification rev 1.0 for more information.)

Following listed the symbols and their respective definitions that are used in the timing

diagram:

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