Zilog Z16C35 - Manual (Page 51)

ISCC
User Manual
UM011002-0808
45
Chapter 4 Data Communication Modes
4.1 INTRODUCTION
The ISCC™ provides two independent full-duplex channels programmable for use in any
common asynchronous or synchronous data communication protocols. The data commu-
nication protocols handled by the SCC cell within the ISCC are:
•
Asynchronous Mode
•
Character-Oriented Mode
•
Monosynchronous
•
Bisynchronous
•
External Synchronous
•
Bit-Oriented Mode
•
SDLC
•
SDLC Loop Mode
4.1.1 General Description of the Transmitter
A block diagram of the transmitter is given in Figure 4-1. The transmitter has an 8-bit
Transmit Data register (WR8) loaded from the internal data bus and a Transmit Shift reg-
ister loaded from either WR6, WR7, or the Transmit Data register. In byte-oriented modes,
WR6 and WR7 can be programmed with sync characters. In Monosync mode, an 8-bit or
6-bit sync character is used (WR6), whereas a 16-bit sync character is used (WR6 and
WR7) in Bisync mode. In bit-oriented synchronous modes, the flag contained in WR7 is
loaded into the Transmit Shift register at the beginning and end of a message.
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