Serial

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The Serial plugin for IO Ninja is a powerful, versatile serial terminal designed for embedded developers, hardware engineers, and IoT enthusiasts. It supports text and binary data views, interleaves serial events with data for a complete timeline, and includes advanced features like regex colorization, real-time checksum calculations, and customizable packet templates.

Basic Setup

Ensure your serial device is connected to the computer that is running IO Ninja.
In IO Ninja, click the “New Session” dropdown and select a new “Serial” session.

If not selected automatically, select your serial device from the “Port:” dropdown.

Open the port by clicking the “Open” button located to the right of the “Port:” dropdown.

Monitor traffic in the “Serial” window.

Adjust settings as needed via the “Settings” button (see “Settings” section below for details).

Craft Serial Packets

In the “Transmit” pane, type your binary packet and press “Send”.

Settings

Setting	Description	Default
Port	The port that should be used.
Reopen on error	Attempt to re-open port if disconnected on error, e.g., due to manual unplug of USB-to-Serial device.	False
Reopen timeout	Delay to insert between re-open attempts.	3000
Baud rate	The serial baud rate.	38400 bps
Data bits	Serial data bit count (word size). See available options.	8 bits
Parity	Serial parity check type. See available options.	None
Stop bits	Serial stop bit count. See available options.	1 bit
Flow control	Serial flow control. See available options.	None
DTR	State of the DTR (Data-Terminal-Ready) modem control line.	True
RTS	State of the RTS (Request-to-Send) modem control line.	False
BREAK	Enable the BREAK condition on the TX line.	False
Read mode (Windows-only)	Advanced read request-specific options. See available options.	Wait for the 1st char
Read inter-char interval (ms) (Windows-only)	Maximum inter-character delay during read request.	10
Read parallelism (Windows-only)	Maximum number of read requests to issue in parallel. Having more than one pending read at a time helps with increasing read throughput when incoming data arrives in rapid streams (after filling one user buffer, the kernel can immediately switch to the next one without any waiting). Increasing this number beyond 4 usually won’t yield any extra performance gains.	4
Read block size (B)	The size of each individual read block submitted to the underlying transport.	4KB
RX buffer size (B)	The full size of the incoming data (RX) buffer. Affects read throughput.	16KB
TX buffer size (B)	The full size of the outbound data (TX) buffer. Affects write throughput..	16KB
Keep read block size	Don’t merge read blocks in RX buffer. Incoming data blocks coming in quick succession can be merged together so that IO Ninja writes them to log as a whole. When this option is set to `True`, blocks are written to the log without merging, i.e., exactly as they are received from the underlying transport..	False
Keep write block size	Don’t merge write blocks in TX buffer. Outbound data blocks sent in quick succession can be merged together before submission to the underlying transport. When this option is set to `True`, blocks are submitted to the transport without merging, i.e., exactly as they are sent by the Transmit or Script panes..	False
RX buffer full notifications	Toggle warnings in log about the incoming data (RX) buffer getting full.	False
Serial setting changes	Toggle notifications about serial setting (baud rate, data size, parity, stop bits, flow control) changes in the log.	on
DTR/RTS changes	Toggle notifications about control line (`DTR`, `RTS`) changes in the log.	on
DSR/CTS/DCD/RI changes	Toggle notifications about status line (`DSR`, `CTS`, `DCD`, `RI`) changes in the log.	on
Serial line errors	Toggle warning about serial line errors (`PARITY`, `FRAMING` and `BREAK`) in the log.	on

Data Bit Options

Option
5 bits
6 bits
7 bits
8 bits

Parity Options

Option	Description
None	No parity bit is used
Odd	Odd parity (parity bit is set when the number of logical ones in the UART frame is odd).
Even	Even parity (parity bit is set when the number of logical ones in the UART frame is even).
Mark	Parity bit is present and always set.
Space	Parity bit is present and always clear.

Stop Bit Options

Option
1 bit
1.5 bits
2 bits

Flow Control Options

Option	Description
None	No flow control.
RTS/CTS	Hardware flow control using CTS and RTS lines.
XON/XOFF	Software flow control using XON and XOFF lines.

Read Mode Options (Windows-only)

Option	Description
Check COMSTAT.cbInQue	Prior to reading, check the status of the incoming buffer of the serial driver. Only read the number of bytes available there.
Wait for the 1st character	Read requests return as soon as possible (as soon as at least one byte arrives).
Interval-based	Read requests keep accumulating bytes until the inter-character delay exceeds the limit specified by “Read inter-char interval (ms)” or the buffer is full.

Note

Typically, it’s best to leave the Read Mode setting at its default (Wait for the 1st character), unless compatibility issues require a change. The default setting is optimal in most situations.