CS8900A datasheet(69/128 Pages) CIRRUS

69 / 128 page

DS271PP3

CS8900A

Crystal LAN™ ISA Ethernet Controller

CIRRUS LOGIC PRODUCT DATA SHEET

4.4.22 Register 19: Test Control

(TestCTL, Read/Write, Address: PacketPage base + 0118h)

TestCTL controls the diagnostic test modes of the CS8900A.

011001

These bits provide an internal address used by the CS8900A to identify this as the Test Control

DisableLT

When set, the 10BASE-T interface allows packet transmission and reception regardless of the

link status. DisableLT is used in conjunction with the LinkOK (Register 14, LineST, Bit 7) as fol-

lows:

LinkOK

DisableLT

No packet transmission for reception

allowed. Transmitter sends link impulses.

DisableLT overrides LinkOK to allow packet

transmission and reception. Transmitter

does not send link pulses.

N/A

Disable has no meaning if LinkOK = 1.

ENDECloop

When set, the CS8900A enters internal loopback mode where the internal Manchester encoder

output is connected to the decoder input. The 10BASE-T and AUI transmitters and receivers

are disabled. When clear, the CS8900A is configured for normal operation.

AUIloop

When set, the CS8900A allows reception while transmitting. This facilitates loopback tests for

the AUI. When clear, the CS8900A is configured for normal AUI operation.

Disable Backoff

When set, the backoff algorithm is disabled. The CS8900A transmitter looks only for completion

of the inter packet gap before starting transmission. When clear, the backoff algorithm is used.

FDX

When set, 10BASE-T full duplex mode is enabled and CRS (Register 14, LineST, Bit E) is ig-

nored. This bit must be set when performing loopback tests on the 10BASE-T port. When clear,

the CS8900A is configured for standard half-duplex 10BASE-T operation.

At reset, if no EEPROM is found by the CS8900A, then the register has the following initial state. If an EEPROM is

found, then the register’s initial value may be set by the EEPROM. See Section 3.3 on page 19.

Reset value is: 0000 0000 0001 1001

765

4321

DisableLT

011001

DCBA

FDX

Disable Back-

off

AUIloop

ENDEC loop

CS8900A Datasheet(PDF) 69 Page - Cirrus Logic

CS8900A Datasheet(HTML) 69 Page - Cirrus Logic

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

Datasheet Download

Link URL