DS3134 datasheet(65/203 Pages) DALLAS

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DS3134

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Bits 0 to 7 / Transmit Channel Number (TCH#). The CPU will load the number of the HDLC channel

associated with this particular DS0 channel. If the port is running in an unchannelized mode (TUEN = 1),

then the HDLC Channel Number only needs to be loaded into T[n]CFG0. If the Fast (52 Mbps) HDLC

Engine is enabled on Port 0, then HDLC Channel 1 is assigned to it and likewise HDLC Channel 2 will

be assigned to the Fast HDLC Engine on Port 2 if it is enabled. Hence, these HDLC channel numbers

should not be used if the Fast HDLC Engines are enabled.

00000000 (00h) = HDLC Channel Number 1 (also used for the Fast HDLC Engine on Port 0)

00000001 (01h) = HDLC Channel Number 2 (also used for the Fast HDLC Engine on Port 1)

00000010 (02h) = HDLC Channel Number 3

11111111 (FFh) = HDLC Channel Number 256

Bit 8 / Transmit 56 kbps (T56). If the port is running a channelized application, this bit determines

whether the LSB of each DS0 should be processed or not. If this bit is set, then the LSB of each DS0

channel will not be routed from the HDLC controller (or the BERT if it has been enabled via the RBERT

bit) and the LSB bit position will be forced to a one.

0 = 64 kbps (use all 8 bits in the DS0)

1 = 56 kbps (use only the first 7 bits transmitted in the DS0; force the LSB to one)

Bit 9 / Transmit Force All Ones (TFAO). If this bit is set, then eight ones will be placed into the DS0

channel for transmission instead of the data that is being sourced from the HDLC controller. If this bit is

cleared, then the data from the HDLC controller will be transmitted. This bit is useful in instances when

Channelized Local LoopBack (CLLB) is being activated to keep the looped back data from being sent out

onto the network. This bit overrides TCHEN.

0 = transmit data from the HDLC controller

1 = force transmit data to all ones

Bit 11 / Channelized Network LoopBack Enable (CNLB). Enabling this loopback forces the receive

data to replace the transmit data. This bit must be set for each and every DS0 channel that is to be looped

back. This bit overrides TBERT, TFAO, and TCHEN.

0 = loopback disabled

1 = loopback enabled

Bit 14 / Route Data from BERT (TBERT). Setting this bit will route DS0 data to the TD pin from the

BERT block instead of from the HDLC controller. If the DS0 channel has been configured for 56 kbps

operation (T56 = 1), then the LSB of each DS0 channel will not be routed from the BERT block but will

be forced to a one instead. In order for the data to make it from the BERT block, the Host must also

configure the BERT for the proper port via the Master Control register (see Section 4). This bit overrides

TFAO and TCHEN.

0 = do not route data from BERT

1 = route data from BERT (override the data from the HDLC controller)

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