SmartGPU2-LCD480X320Touch-CommandSet

SMART GPU 2 3.5” TOUCH

Command Set

2.9.6 Open File –4Fhex – ‘O’ ascii

Commands (host)

4 bytes + file name with “.ext” + 1byte(NULL).

1.- 0x46 (hex), F (ascii). *FAT command.

2.- 0x4F (hex), O (ascii). (Open File)

3.- Workspace Block# 0x00(hex) – 0x03(hex).

4.- Open Mode:

0x01 (hex)- Read Only

0x02 (hex)- Write Only

0x03 (hex)- Read +Write

5 up to N (file name including extension).

N+1.- 0x00 (hex) NULL ascii.

Responses (device)

1 byte File ACK + 1 byte Command ACK

1.- 0xXX (hex) - Refer to “File ACK List”.

2.- 0x4F (hex), O (ascii) – success ACK.

0x46 (hex), F (ascii) – fail NAK.

Description

This Command Opens/Allocates a file on the

Workspace Block# parameter, the file access

depends on the “Open Mode” parameter:

- Read Only: Specifies read access to the object,

file data can only be read, not write.

- Write Only: Specifies write access to the object,

file data can only be write, not read.

- Read+Write: Specifies read+write access to the

object, file data can be write or read.

After Open File command is executed and

succeeds(ACK), the file object workspace block

is valid. The file object workspace block is used

for subsequent read/write operations to identify

the file.

Only one file can be open at the same time in

the same Workspace block, always be sure close

a Workspace block file object before opening a

new one in it, if another file is already allocated in

the Workspace block and a call to “Open File” is

executed in that same Workspace block, the old

file is discarded and replaced by the new one,

any unsaved changes on the old file will be lost.

To save changes to file without closing it use “Sync

File”, to save and close an open file object use “Close

File” function. If the modified/written file is not saved or

closed, the file data can be collapsed.