AM79C971VCW datasheet(189/265 Pages) AMD

189 / 265 page

Am79C971

189

mit frame, where Excessive De-

ferral is defined in the ISO 8802-3

(IEEE/ANSI 802.3) standard. Ex-

cessive Deferral will also set the

interrupt bit EXDINT (CSR5, bit

7).

LCOL

Late Collision indicates that a col-

lision has occurred after the first

channel slot time has elapsed.

The Am79C971 controller does

not retry on late collisions. LCOL

is set by the Am79C971 controller

and cleared by the host.

LCAR

Loss of Carrier is set when the

carrier

lost

during

Am79C971

controller

initiated

transmission when in AUI mode

and the device is operating in

half-duplex

mode.

The

Am79C971 controller does not

retry upon loss of carrier. It will

continue to transmit the whole

frame until done. LCAR will not

be set when the device is operat-

ing in full-duplex mode and the

AUI port is active. LCAR is not

valid in Internal Loopback Mode.

LCAR is set by the Am79C971

controller and cleared by the

host.

LCAR does not reflect a link sta-

tus problem on the external PHY.

In 10BASE-T mode, LCAR will be

set when the T-MAU was in Link

Fail state during the transmis-

sion.

RTRY

Retry error indicates that the

transmitter has failed after 16 at-

tempts to successfully transmit a

message, due to repeated colli-

sions on the medium. If DRTY is

set to 1 in the MODE register,

RTRY will set after one failed

transmission attempt. RTRY is

set by the Am79C971 controller

and cleared by the host.

25-16

RES

Reserved locations.

15-4

RES

Reserved locations.

3-0

TRC

Transmit Retry Count. Indicates

the number of transmit retries of

the associated packet. The maxi-

mum count is 15. However, if a

RETRY error occurs, the count

will roll over to 0.

In this case only, the Transmit

Retry Count value of 0 should be

interpreted as meaning 16. TRC

is written by the Am79C971 con-

troller into the last transmit de-

scriptor of a frame, or when an

error terminates a frame. Valid

only when OWN is cleared to 0.

TMD3

Bit

Name

Description

31-0

User Space. Reserved for user

defined space.

AM79C971VCW датащи(PDF) 189 Page - Advanced Micro Devices

AM79C971VCW датащи(HTML) 189 Page - Advanced Micro Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL