MT9173AN1 Ver la hoja de datos (PDF) - Zarlink Semiconductor Inc

Número de pieza

componentes Descripción

Fabricante

MT9173AN1

ISO2-CMOS ST-BUS™ FAMILY Digital Subscriber Interface Circuit with RxSB Digital Network Interface Circuit with RxSB

Zarlink Semiconductor Inc 

MT9173/74

Data Sheet

In order for more than one DNIC to be connected to any one DV and CD port, making more efficient use of the

busses, the DSTo and CDSTo outputs are put into high impedance during the inactive channel times of the DNIC.

This allows additional DNICs to be cascaded onto the same DV and CD ports. When used in this way a signal

called F0o is used as an indication to the next DNIC in a daisy chain that its channel time is now active. Only the

first DNIC in the chain receives the system frame pulse and all others receive the F0o from its predecessor

in the chain. This allows up to 16 DNICs to be cascaded.

CD Port (CDSTi/CDi, CDSTo/CDo)

The CD port is a serial bidirectional port used only in DUAL port mode. It is a means by which the DNIC receives its

control information for things such as setting the bit rate, enabling internal loopback tests, sending status

information back to the system and transferring low speed signalling data to and from the line.

The CD port is composed of the C and D-Channels. The C-channel is used for transferring control and status

information between the DNIC and the system. The D-channel is used for sending and receiving signalling

information and lower speed data between the line and the system. In DN/DUAL mode the DNIC receives a C-

channel on CDSTi while transmitting a C-channel on CDSTo. Fifteen channel times later (halfway through the

frame) a D-channel is received on CDSTi while a D-channel is transmitted on CDSTo. This is shown in Figure 7.

The order of the C and D bytes in DUAL port mode can be reversed by the mode select pins. See Table 1 for a

listing of the byte orientations.

The D-channel exists only in DN mode and may be used for transferring low speed data or signalling information

over the line at 8, 16 or 64 kbit/s (by using the DINB feature). The information passes transparently through the

DNIC and is transmitted to or received from the line at the bit rate selected in the Control Register.

If the bit rate is 80 kbit/s, only D0 is transmitted and received. At 160 kbit/s, D0 and D1 are transmitted and

received. When the DINB bit is set in the Control Register the entire D-channel is transmitted and received in the

B1-channel timeslot.

The C-channel is used for transferring control and status information between the DNIC and the system. The

Control and Diagnostics Registers are accessed through the C-channel. They contain information to control the

DNIC and carry out the diagnostics as well as the HK bit to be transmitted on the line as described in Tables 4 and

5. Bits 0 and 1 of the C-channel select between the Control and Diagnostics Register. If these bits are 0, 0 then the

C-channel information is written to the Control Register (Table 4). If they are 0, 1 the C-channel is written to the

Diagnostics Register (Table 5).

11

Zarlink Semiconductor Inc.

Share Link: