SIO Command $DC Open App Key

Open App Key ($DC)

Description

This command is required prior to performing a Write App Key or Read App Key command, as it sets the details needed for the key.

A six-byte buffer is sent from the Atari to FujiNet with the following information:

Size	Value	Notes
2 bytes	creator ID	see below
1 byte	app ID	Creator-specified value (0-255)
1 byte	key ID	Creator-specified value (0-255)
1 byte	open mode	0 = read, 1 = write
1 byte	reserved	0 - currently unused

App keys are stored as files in the /FujiNet directory on the SD card. Note that only SD storage is currently supported for app key storage, and app key reads/writes will fail if no SD card is installed. The file name is constructed using the hexadecimal values for creator, app, and key. e.g. /FujiNet/B0C1010A.key

There's currently no need to close an app key, as it is immediately closed after an App Key Read or Write operation. The close function may be used in the future.

Creator IDs

This is an unsigned 16-bit value, which should allow for more than enough creators. Values from 0-255 (0x00-0xFF) are reserved for internal use by FujiNet - please don't use any value in this range.

Although there's currently no official registry for FujiNet Creator ID's, we will document them here as we're informed they're in use.

Known Creator IDs

• 0x00-0xFF Reserved for FujiNet use
• 0xB0C1 - @bocianu
• 0xB177 - @billkendrick

Parameters

DCB	Value
DDEVIC	$70
DUNIT	$01
DCOMND	$DC
DSTATS	$80
DBUF	Pointer 6-byte buffer with structure specified above
DTIMLO	15
DBYT	6
DAUX	Not used

Examples

See appkey-sample in the fujinet-apps repository.

See Also

• Read App Key
• Write App Key