DS2180A Ver la hoja de datos (PDF) - Dallas Semiconductor -> Maxim Integrated

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componentes Descripción

Fabricante

DS2180A

T1 Transceiver

Dallas Semiconductor -> Maxim Integrated 

ACB: ADDRESS COMMAND BYTE Figure 4

(MSB)

-

FRSR2 EYELMD

FM

SYELMD

B8ZS

DS2180A

(LSB)

B7

LPBK

SYMBOL

-

FRSR2

EYELMD

FM

SYELMD

B8ZS

B7

LPBK

POSITION

CCR.7

CCR.6

CCR.5

CCR.4

CCR.3

CCR.2

CCR.1

CCR.0

NAME AND DESCRIPTION

Reserved, must be 0 for proper operation.

Function of REC Status Register 2.

0 = Detected B8ZS code words reported at RSR.2.

1 = COFA (Change-of-Frame Alignment) reported at RSR.2 when

last resync resulted in change of frame or multiframe alignment.

193E Yellow Mode Select.

0 = Yellow alarm is a repeating pattern set of 00 hex and FF hex.

1 = Yellow alarm is a 0 in the bit 2 position of all channels.

Frame Mode Select.

0 = D4 (193S, 12 frames/superframe).

1 = Extended (193E, 24 frames/superframe).

193S Yellow Mode Select. Determines yellow alarm type to be

transmitted and detected while in 193S framing. If set, yellow

alarms are a 1 in the S-bit position of frame 12; if cleared, yellow

alarm is a 0 in bit 2 of all channels. Does not affect 193E yellow

alarm operation.

Bipolar eight zero substitution.

0 = No B8ZS.

1 = B8ZS enabled.

(Note: This bit must be set to 0 when CCR.1=1)

Bit seven zero suppression. If CCR.1=1, channels with an all zero

content will be transmitted with bit 7 forced to 1. If CCR.1=0, no

bit 7 stuffing occurs.

(Note: This bit must be set to 0 when CCR.2=1)

Loopback. When set, the device internally loops output transmit

data into the incoming receive data buffers and TCLK is internally

substituted for RCLK.

LOOPBACK (Refer to Figure 4)

Enabling loopback will typically induce an out-of-frame (OOF) condition. If appropriate bits are set in

the receive control register, the receiver will resync to the looped transmit frame alignment. During the

looped condition, the transmit outputs (TPOS, TNEG) will transmit unframed all 1's. All operating modes

(B8ZS, alarm, signaling, etc.) except for blue alarm transmission are available in loopback.

BIT SEVEN STUFFING

Existing systems meet 1's density requirements by forcing bit 7 of all zero channels to 1. Bit 7 stuffing is

globally enabled by asserting bit CCR.1 and may be disabled on an individual channel basis by setting

appropriate bits in TTR1–TTR3. Bit 7 stuffing and B8ZS modes should not be enabled simultaneously.

Enabling both results in LOS.

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