CS8952 Datasheet, PDF(25/82 Page) Cirrus Logic – CrystalLAN 100BASE-X and 10BASE-T Transceiver

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CS8952 Datasheet, PDF (25/82 Pages) Cirrus Logic – CrystalLAN 100BASE-X and 10BASE-T Transceiver

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CS8952

Manchester Encoder and Decoder. Selection is

made via:

- setting bit 14 in the Basic Mode Control

- setting bits 8 and 11 in the Loopback, By-

pass, and Receiver Error Mask Register

(address 18h) or

- asserting the LPBK pin.

3.1.3.7 Carrier Detection

The carrier detect circuit informs the MAC that val-

id receive data is present by asserting the Carrier

Sense signal (CRS) as soon it detects a valid bit pat-

tern (1010b or 0101b for 10BASE-T). During nor-

mal packet reception, CRS remains asserted while

the frame is being received, and is de-asserted

within 2.3 bit times after the last low-to-high tran-

sition of the End-of-Frame (EOF) sequence. When-

ever the receiver is idle (no receive activity), CRS

is de-asserted.

3.1.4 10BASE-T Serial Application

This mode is selected when pin 10BT_SERis as-

serted during power-up or reset, and operates simi-

lar to the 10BASE_T MII mode except that data is

transferred serially on pins RXD0 and TXD0 using

a 10 MHz RX_CLK and TX_CLK. Receive data is

framed by CRS rather than RX_DV.

3.2 Auto-Negotiation

The CS8952 supports auto-negotiation, which is

the mechanism that allows the two devices on ei-

ther end of an Ethernet link segment to share infor-

mation and automatically configure both devices

for maximum performance. When configured for

auto-negotiation, the CS8952 will detect and auto-

matically operate full-duplex at 100 Mb/s if the de-

vice on the other end of the link segment also

supports full-duplex, 100 Mb/s operation, and

auto-negotiation. The CS8952 auto-negotiation ca-

pability is fully compliant with the relevant por-

tions of section 28 of the IEEE 802.3u standard.

The CS8952 can auto-negotiate both operating

speed (10 versus 100 Mb/s), duplex mode (half du-

plex versus full duplex), and flow control (pause

frames), or alternatively can be set not to negotiate.

At power-up and reset times, the auto-negotiation

mode is selected via the auto-negotiation input pins

(AN[1:0]). This selection can later be changed us-

ing the Auto-Negotiation Advertisement Register

(address 04h).

Pins AN[1:0] are three level inputs, and have the

function shown in Table 5.

CrystalLANâ¢ 100BASE-X and 10BASE-T Transceiver

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