Hardware Function Usage

Login

There are two ways to log in to the AIBOX-3576: one is terminal login through the Console (Debug Serial), and the other is login through HDMI.

Console Login (Debug Serial)

Connect the Type-C cable to the Console port. The login account is root, and no root password is set by default.
Use the following serial port parameters:

• Baud rate: 115200
• Data bits: 8
• Stop bits: 1
• Parity check: None
• Flow control: None

Serial Debugging on Windows

After connecting the board to the computer with a Type-C cable, the system will prompt that new hardware is found and complete the initialization. Then you can find the corresponding COM port in Device Manager:

On Windows, putty or SecureCRT is generally used. Here we recommend the free version of MobaXterm, which is a powerful terminal software. Other serial port software is used in a similar way.

1. Select Serial as the session type.
2. Set the Serial port to the COM port found in Device Manager.
3. Set Speed (bsp) to 115200.
4. Click the OK button.

Serial Debugging on Ubuntu

Install minicom:

sudo apt-get install minicom

Use minicom -s to open the configuration interface, enter Serial port setup, and set the serial port parameters to 115200 8N1:

• E - Bps/Par/Bits: 115200 8N1
• F - Hardware Flow Control: No
• G - Software Flow Control: No

Note: Both Hardware Flow Control and Software Flow Control must be set to No, otherwise input may become impossible.

After the configuration is completed, select Save setup as dfl to save it as the default configuration. After exiting, minicom will connect to the debug serial port at 115200-8-N-1. Log in with the root account (no password is set by default).

HDMI Login

When logging in via the HDMI, it automatically logs in as the user firefly, with the password also being firefly.

Watchdog

AIBOX-3576 comes with an external watchdog.The device names for the external watchdogs is /dev/wdt_core. For example, using /dev/wdt_core, the procedure is as follows:

# Write to different fields to enable the watchdog and set the time.
# The numbers 0, 1, 2, and 3 represent 0.64s, 2.56s, 10.24s, and 40.96s, respectively.
# The letter 'e' indicates enabling the watchdog, while the letter 'd' indicates disabling it.

# Enable and set the timer for 10.24 seconds. You need to write to it once every 10.24 seconds. You can also write different numbers at any time to change the timing.
echo e >/dev/wdt_core #Enable
echo 2 >/dev/wdt_core #Set the timeout to 10.24 seconds.

RTC

Introduction

AIBOX-3576 has an external RTC powered by a capacitor on the external motherboard, which ensures the RTC continues to run for a short period after power loss. In the kernel, it is represented as rtc0.

Interface Usage

Linux provides three user-space interfaces for interacting with the RTC. The paths are:

• SYSFS interface: /sys/class/rtc/rtc0/
• PROCFS interface: /proc/driver/rtc
• IOCTL interface: /dev/rtc0

Synchronize the current system time to the RTC.

hwclock -w

SYSFS interface

You can directly use cat and echo to operate the interfaces under /sys/class/rtc/rtc0/.

For example, to view the current RTC date and time:

# cat /sys/class/rtc/rtc0/date
2024-07-10
# cat /sys/class/rtc/rtc0/time
02:36:30

PROCFS interface

To print RTC-related information:

# cat /proc/driver/rtc
rtc_time        : 02:37:00
rtc_date        : 2024-07-10
alrm_time       : 00:00:00
alrm_date       : 1970-01-01
alarm_IRQ       : no
alrm_pending    : no
update IRQ enabled      : no
periodic IRQ enabled    : no
periodic IRQ frequency  : 1
max user IRQ frequency  : 64
24hr            : yes

IOCTL interface

You can use ioctl to control /dev/rtc0。

For detailed usage instructions, please refer to document kernel-jammy-src/Documentation/admin-guide/rtc.rst 。