dp8344b National Semiconductor Corporation, dp8344b Datasheet - Page 46

• Manufacturer Part Number: dp8344b
• Description: Biphase Communications Processor?bcp
• Manufacturer: National Semiconductor Corporation

2 0 CPU Description
FIGURE 2-36 DP8344B Operation with External Clock
FIGURE 2-35 DP8344B Operation with Crystal
FIGURE 3-1 System Block Diagram Showing Details of the Line Interface
(Continued)
TL F 9336 – F8
TL F 9336 – F9
46
3 0 Transceiver
3 1 TRANSCEIVER ARCHITECTURAL DESCRIPTION
The transceiver section operates as an on-chip indepen-
dent peripheral implementing all the necessary formatting
required to support the physical layer of the following serial
communications protocols
The CPU and transceiver are tightly coupled through the
CPU register space with the transceiver appearing to the
CPU as a group of special function registers and three dedi-
cated interrupts The transceiver consists of separate trans-
mitter and receiver logic sections each capable of indepen-
dent operation communicating with the CPU via an asyn-
chronous interface This interface is software configurable
for both polled and interrupt-driven interaction allowing the
system designer to optimize his product for the specific ap-
plication
The transceiver connects to the line through an external line
interface circuit which provides the required DC and AC
drive characteristics appropriate to the application A block
diagram of such an interface is shown in Figure 3-1 An on-
chip differential analog comparator optimized for use in a
transformer coupled coax interface is provided at the input
to the receiver Alternatively if an external comparator is
necessary the input signal may be routed to the DATA-IN
pin



IBM 3270 (including 3299)
IBM 5250
NSC general purpose 8-bit
TL F 9336 – 33