4) Device Control Commands

A) BEEP

Feature: Create a beep tone
Format: BEEP <frequency> <duration>
Parameters:

<frequency>	tone frequency in Hz (e.g. 100~10000)
<duration>	tone duration in milliseconds (e.g. 100~10000)

Return Value: None
Example: BEEP 100 10000

B) POWER_OFF

Feature: Turns off the device
Format: POWER_OFF
Parameters: None
Return Value: None
Example: POWER_OFF

C) READ_ENV

Feature: Obtain the environment variable values
Format: READ_ENV <environment variable name>
Parameters:

<environment variable name>	Description
LAST_PATH	the last hard drive backup folder path name
FOLDER_SERIAL	backup folder serial number
ROOT_PATH	designated backup path on the hard drive

Return Value: Environment variable value stored in the variable $ENV
Example: READ_ENV LAST_PATH

D) SCAN_CARD

Feature: Scans a memory card
Format: SCAN_CARD <memory card name>
Parameters:

<memory card name>	Description
CF	Access CF memory card information.
SD	Access SD memory card information.
ANY	Test all memory card slots, access information of the first memory card detected. Testing priority is as follows: CF > SD > MS > xD

Return Value:
If the specified memory card exists, the variable $CARD_PATH will store the path name of the memory card. The variable $CARD_CAPACITY will store the remaining capacity of the memory card in Mbytes.
If the specified the memory card does not exists, the variable $CARD_PATH will return "NOCARD"

Example: SCAN_CARD ANY

E) WAIT_KEY

Feature: Waits for user keystrokes
Format: WAIT_KEY <waiting time>
Parameters: <waiting time> e.g. 1~240 seconds

Return Value:
If a button is pressed during the waiting time, the keystroke value will be stored in the variable $KEY, otherwise $KEY will return "NOKEY". Below is the full list of keystroke values for all the buttons found on COLORSPACE UDMA.

[KEY_MENU][KEY_UP][KEY_ZOOMIN]
[KEY_LEFT][KEY_RIGHT]
[KEY_BACK][KEY_DOWN][KEY_ZOOMOUT]

Example: WAIT_KEY 240

F) SET_USB_HOST

Feature: Activates USB OTG
Format: SET_USB_HOST <switch>
Parameters:

<switch>	Description
On	Activates USB OTG, port becomes USB Host
Off	Deactivates USB OTG, port becomes USB Device

Return Value: None

Note: Command will not change the USB port status immediately. Instead, the port status will only change the next time the file directory is accessed. Consider using SELECT_FOLDER command right after SET_USB_HOST command if you wish to change the USB port status immediately.

Example: SET_USB_HOST On