====== KBI - Khadas Bootloader Instructions ======

This page introduces KBI. You will learn how to manage the status of a Khadas SBC through KBI.

<WRAP important >
Khadas Bootloader Instructions (KBI) can be used to:
  * Manage the programmable MCU. 
  * Perform low-level hardware management. 
  * Enable developers to utilize all the features of Khadas SBCs. </WRAP>

<WRAP info >
This page uses VIM2 as an example. 
</WRAP>

===== Uboot usage =====

To get started, ensure you have booted into U-Boot:

```shell
normal power off
boot wol: enable
Hit Enter or space or Ctrl+C key to stop autoboot -- :  0 
kvim2# _
```

==== Help information =====

You can get help information by typing ''kbi'':

```shell
kvim2# kbi
kbi - Khadas Bootloader Instructions sub-system

Usage:
kbi [function] [mode] [write|read] <value>

kbi version - read version information
kbi usid - read usid information
kbi adc - read adc value
kbi powerstate - read power on state
kbi poweroff - power off device
kbi ethmac - read ethernet mac address

kbi led [systemoff|systemon] w <off|on|breathe|heartbeat> - set blue led mode
kbi led [systemoff|systemon] r - read blue led mode

kbi bootmode w <emmc|spi> - set bootmode to emmc or spi
kbi bootmode r - read current bootmode

kbi trigger [wol|rtc|ir|dcin|key|gpio] w <0|1> - disable/enable boot trigger
kbi trigger [wol|rtc|ir|dcin|key|gpio] r - read mode of a boot trigger
```

==== MCU Verison ====

Get the MCU firmware version:

```shell
kvim2# kbi version
version: 03
```

==== Initialize ====

Initialize the KBI:

```shell
kvim2# kbi init
```

==== Serial number ====

Get the device serial number:

```shell
kvim2# kbi usid
usid: 000000
```

==== ADC ====

Get ADC value:
```shell
kvim2# kbi adc
adc: 0x236
```

The ADC value can be used to distinguish between different hardware modules.

==== Power Off ====

Power off the device:
```shell
kvim2# kbi poweroff
```

==== MAC Address ====

Get the Ethernet MAC address:
```shell
kvim2# kbi ethmac
mac address: 98:aa:fc:60:44:c0
```

==== LED Control ====

The blue LED has four operating modes: ''Always Off'', ''Always On'', ''Breathe'', and ''Heartbeat''. It indicates the VIM's operating status.

The MCU, which handles system power management, controls the blue LED. The CPU controls the white LED.
Therefore, the blue LED continues to function even when the VIM2 is powered off.

KBI can be used to program the blue LED for two operating modes:

  * system off / idle: Power-off status, the CPU is in a power-down mode.
  * system on / working: Power-on status, the CPU is in working mode.

Example:

To check the blue LED’s setting for ''system off'' / idle status:

```shell
kvim2# kbi led systemoff r
led mode: breathe  [systemoff]
```

Check the blue LED setting for ''system on'' / working status:

```shell
kvim2# kbi led systemon r
led mode: off  [systemon]
```
When the VIM2 is powered on, the blue LED is set to ''Always Off'' by default.

You can reset it to ''breathe'' mode: 
```shell
kvim2# kbi led systemon w breathe
```

You can also change the setting for ''system on'' / working status:

```shell
kvim2# kbi led systemon w Heartbeat
```

==== Boot Mode ====

You can flash images to either SPI flash or eMMC storage on the VIM2, and use KBI to set one of them as the default boot media.

Set the default boot media to SPI flash:
```shell
kvim2# kbi bootmode w spi
```

Set default boot media to eMMC storage:

```shell
kvim2# kbi bootmode w emmc
```

You can check the current default boot media setting:

```shell
kvim2# kbi bootmode r
bootmode: emmc
```

==== Boot Trigger Events ====

The VIM2 supports several events to trigger boot-up:
  * WOL: Wake-on-Lan
  * RTC: RTC timer
  * IR: IR remote controller
  * DCIN: Plug in the DC adapter
  * Key: Power Key/Button
  * GPIO: External GPIO events
This means any of the above events can trigger the VIM2 to power on, provided that the specific trigger event has been enabled.

For example:

  * Get the status of the WOL trigger event:
```shell
kvim2# kbi trigger wol r
boot wol: disable
```
  * WOL is disabled by default in the pre-installed ROM. You can enable it:
```shell
kvim2# kbi trigger wol w 1
set_wol: 1
```
  * For security reasons, you may want to disable WOL: reasons. : 
```shell
kvim2# kbi trigger wol w 0
set_wol: 0
```

====== Read for reference ======

  * [[dl>products/edge1/tools/mcu/edge-v_mcu_reg_en.pdf|Edge-V MCU Register Map]]
  * [[dl>products/vim2/tools/mcu/vim2_mcu_reg_en.pdf|VIM2 MCU Register Map]]
  * [[dl>products/vim3/tools/mcu/vim3_mcu_reg_en.pdf|VIM3 MCU Register Map]]