µ
DRIVE
-
uSD
-
G1
www.4dsystems.com.au
12
2.3.3
W
rite Sector Block Data
(
@W
)
Syntax :
extCmd, cmd, SectorAddress(hi:mid:lo), data(1), .. , data(512)
extCmd : 40hex, @ascii
cmd : 57hex, Wascii
SectorAddress(hi:mid:lo): A 3 byte sector address. Sector Address range from 0 to
16,777,215 depending on the capacity of the memory card used in the module. Each
sector is 512 bytes in size. There are 2048 sectors per every 1Mb of µ
DRIVE
memory.
data(1), .. , data(512): 512 bytes of sector data. The data length must be 512 bytes
long. Unused bytes must be padded even if not all are used.
Description :
This command allows downloading and writing large amounts of data
to the µ
DRIVE
. Downloads must always be limited to 512 bytes in length. For large
volumes of data such as images, the data must be broken up into multiple sectors
(chunks of 512 bytes) and this command then maybe used many times until all of the
data is written into the µ
DRIVE
. If the data block to be written is less than 512 bytes
in length, then make sure the rest of the remaining data are padded with 00hex or
FFhex (it can be anything).
If only few bytes of data are to be written then the Write Byte command can be
used.
Once this command message is sent, the µ
DRIVE
will take a few milliseconds to write
the data into its memory card and at the end of which it will reply back with an
ACK
(06hex) if the write cycle was successful. If there was a problem in writing the data, a
NAK
(15hex) will be sent back without any write attempts.
Only data(1) to data(512) are written to the sector. Other bytes in the command
message such as Sector Address are not stored.
