Hardware Function Usage

Debug Serial

The AIBOX-K3 has an onboard Type-C Console debug serial port. No external serial module is required: just connect the host to the PC with a Type-C cable for serial debugging.

For the connection and usage of the debug serial port, see: Debug Serial.

Login

There are two ways to login to AIBOX-K3, one is via Console (Debug serial), the other is via HDMI.

Console Login (Debug Serial)

Type-C Connects to the Console port. The login account is root. By default, the root password is not set.
Use the following serial port parameters:

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

HDMI Login

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

Watchdog

AIBOX-K3 comes with an external watchdog.The device names for the external watchdogs is /dev/wdt_base. For example, using /dev/wdt_base, 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_base #Enable
echo 2 > /dev/wdt_base #Set the timeout to 10.24 seconds.

RTC

Introduction

AIBOX-K3 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 。