Serial Interfaces; Table 3-4. Serial 1 (Com1) Interface Pin Signal Descriptions (J18) - ADLINK Technology CoreModule 920 Reference Manual

Chapter 3

Serial Interfaces

The CoreModule 920 provides two RS-232 serial ports. The PCH BD82QM67 contains the circuitry for
both serial ports and delivers the signals through two RS-232 transceivers: one transceiver for COM1 and
the second transceiver for COM2. The serial ports support the following features:
•
Two individual high-speed NS16C550A-compatible UARTs (COM1 and COM2)
•
Programmable word length, stop bits, and parity
•
16-bit programmable baud rate generator
•
Loop-back mode
•
Two individual 16-bit FIFOs
•
Serial Port Headers
J18 - Serial 1 (COM1) supports RS-232 and full modem

H16 - Serial 2 (COM2) supports RS-232 and full modem

Table 3-4 defines the pins and corresponding signals for serial 1 header (J18), which consists of 10 pins, 2
rows, odd/even sequence (1, 2), and 0.079" (2mm) pitch.

Table 3-4. Serial 1 (COM1) Interface Pin Signal Descriptions (J18)

Pin # Signal
1 S1_DCD*
2 S1_DSR*
3 S1_RXD
4 S1_RTS*
5 S1_TXD
6 S1_CTS*
7 S1_DTR*
8 S1_RI*
9 GND
10 GND
Note: The shaded table cell denotes ground. The * symbol indicates the signal is Active Low.
CoreModule 920
DB9 Description
Pin #
1 COM1 Data Carrier Detect – Indicates external serial device is detecting
a carrier signal (i.e., a communication channel is currently open). In
direct connect environments, this input is driven by DTR as part of the
DTR/DSR handshake.
6 COM1 Data Set Ready – Indicates external serial device is powered,
initialized, and ready. Used as hardware handshake with DTR for overall
readiness.
2 COM1 Receive Data – Serial port receive data input is typically held at a
logic 1 (mark) when no data is being transmitted, and is held "Off" for a
brief interval after an "On" to "Off" transition on the RTS line to allow
the transmission to complete.
7 COM1 Request To Send – Indicates serial port is ready to transmit data.
Used as hardware handshake with CTS for low level flow control.
3 COM1 Transmit Data – Serial port transmit data output is typically held
to a logic 1 when no data is being sent. Typically, a logic 0 (On) must be
present on RTS, CTS, DSR, and DTR before data can be transmitted on
this line.
8 COM1 Clear To Send – Indicates external serial device is ready to
receive data. Used as hardware handshake with RTS for low level flow
control.
4 COM1 Data Terminal Ready – Indicates serial port is powered,
initialized, and ready. Used as hardware handshake with DSR for overall
readiness.
9 COM1 Ring Indicator – Indicates external serial device is detecting a
ring condition. Used by software to initiate operations to answer and
open the communications channel.
5 Ground
10 Ground
Reference Manual
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