Table of Contents
Advertisement
linking. The interrupt structure is also programmable so that the on-chip
M68000 processor can be off-loaded from the peripheral bit-handling func-
tions to perform higher layer application software or protocol processing.
1.4 NMSI COMMUNICATIONS-ORIENTED ENVIRONMENT
When the interface to equipment or proprietary networks requires the use
of standard control and data signals, the MC68302 can be programmed into
the NMSI mode. This mode, which is available for one, two, or all three SCC
ports, can be selected while the other ports use one of the multiplexed inter-
face modes (IDL, GCI, or PCM highway).
In the example shown in Figure 1-4, one SCC channel connects through the
NMSI mode to a commercial packet data network. This connection might be
used for remote status monitoring or for maintenance functions for a system.
The other SCC channel is used as a local synchronous channel, which could
connect to another computer or subsystem. The SCP channel could then be
used for local interconnection of interface chips or peripherals to the MC68302-
based system.
1.5 BASIC RATE ISDN OR DIGITAL VOICE/DATA TERMINAL
1-6
A basic rate ISDN or digital voice/data terminal can be made from a chip set
based on the MC68302. Refer to Figure 1-5 for an example of a basic rate
ISDN voice/data terminal. In this terminal, the CP can directly support the
28
+
D channels. The physical layer serial interface is connected to the local
interconnection bus (IDL in Figure 1-5, but the GCI and PCM buses can also
be supported). The system then supports one of the B channels for voice
(connected directly to the physical bus). The D channel consists of one SCC
port; the other B channel is used for data transfer through a second SCC
port. The data can be routed to a terminal (RS-232 type) via the third SCC
port in the NMSI mode. The SCP can function as a peripheral chip setup
channel for IDL bus uses or as a general-purpose communications channel
for devices using SCP-channel format.
Some physical layer devices support the signaling and framing functions of
the D channel. In these cases, the D channel connects through the micro-
processor interface to the physical layer device, and the remaining
sec
port
can be used for a second B channel to transfer data.
MC68302 USER'S MANUAL
MOTOROLA
Advertisement
Table of Contents
