Z16C30_08 Datasheet, PDF (48/102 Pages) Zilog, Inc. – CMOS USC Universal Serial Controller

Z16C30
Product Specification
44
Data
1
1
0
0
1
0
NRZ
NRZB
NRZI-M
NRZI-S
BI-PHASE-M
BIPHASE-S
BIPHASE-L
DIFFERENTIAL
BIPHASE-L
Figure 28. Data Encoding
Differential Biphase-Level—In Differential Biphase-Level, a 1 is represented by a transi-
tion at the center of the bit cell, with the opposite polarity from the transition at the center
of the preceding bit cell. A 0 is represented by a transition at the center of the bit cell with
the same polarity as the transition at the center of the preceding bit cell. In both cases there
may be transitions at the beginning of the bit cell to set up the level required to make the
correct center transition.
Character Counters
Each channel in the USC contains a 16-bit character counter for both receiver and trans-
mitter. The receive character counter may be preset either under software control or auto-
matically at the beginning of a receive message. The counter decrements with each receive
character and at the end of the receive message the current value in the counter is automat-
DS007902-0708
PRELIMINARY
Functional Description