HD64570 Datasheet, PDF (70/469 Pages) Hitachi Semiconductor – Serial Communications Adaptor

Table 2.9 Serial I/O (MSCI) Lines (cont)
Pin Number
Input/
Output
Symbol CP-84
FP-88
Description
RTS0,
RTS1
66, 56
80, 70
Output
Request to send for MSCI: Indicates that the
SCA has data to output to a communications
device such as a modem. The output level on
this line can be automatically controlled by
MSCI operation (auto-enable function).
This line can also be used as a general-purpose
output port.
DCD0,
DCD1
67, 57
81, 71
Input
Data carrier detect for MSCI: Indicates that a
communications device such as a modem is
receiving valid data from the communication
line. MSCI receive operations can be
automatically controlled by this input (auto-
enable function). This line can also be used as
a general-purpose input port.
CTS0,
CTS1
68, 58
82, 72
Input
Clear to send for MSCI: Indicates that a
communications device such as a modem is
ready to send data to the communication line.
MSCI transmit operations can be automatically
controlled by this input (auto-enable function).
This line can also be used as a general-purpose
input port.
SYNC0,
SYNC1
64, 55
78, 69
Input/
output
Synchronization for MSCI: Input line in external
byte output synchronous mode.
Synchronization is established at the falling
edge of SYNC0 or SYNC1. This line is an
output line in mono-sync and bi-sync byte
synchronous modes and bit synchronous HDLC
mode.
It indicates the inverse of the SYNCD/FLGD bit
in MSCI status register 1 (ST1). In mono-sync
or bi-sync byte synchronous mode, a low pulse
is output immediately after a SYN pattern is
detected. In bit synchronous HDLC mode, a low
pulse is output immediately after a flag pattern
is detected.
In asynchronous mode, this line is an input line,
but the input value does not affect operations.
Note: For details concerning MSCI status register 1 (ST1), see section 5.2.1, MSCI Status
Register 1.
Rev. 0, 07/98, page 54 of 453