Axiohm A795, Руководство пользователя

Страница: 104 / 128

A795 User Guide: Programming Supplement
Chapter 4: Commands listed by hexadecimal code
104
User storage status (ColorPOS™)
ASCII GS 0x97 m n
Hexadecimal 1D 97 m n
Decimal 29 151 m n
Value of m: m specifies the type of stored object to
be reported:
m = 0 return the kilobytes (1024) of free user RAM,
n = 0 gets largest free block size
n = 1 gets the total size free
m = 1 return the kilobytes of free character & logo flash
memory, n = 0
m = 2 return the kilobytes of free user data flash
memory, n = 0
m = 3 return the CRC of a logo indexed by n
m = 4 return the CRC of a downloaded character set,
selected by n
m = 5 return the CRC of a macro that has been
stored, n = 0
For m = 0 the value of n selects a return of either the
largest free block or total free size, since
contiguous allocation cannot be assumed as
this area is completely under user control
through address parameters.
n = 0 if only one instance of an object type is allowed
(macro, user data, user defined characters).
n is the item index when more than one object of
type m is possible
n <= FE, see the comments about logo and character set
indexes
n = FF : return a list describing all the existing items
of type m
Note: When a specific item request is made, a returned
CRC value of 0 0 indicates that no item is stored at that
index. There is a practically negligible possibility that a
valid object will have a 0 0 CRC; if this is of concern,
applications should check the object downloaded byte
sequence to verify that this is not the case (as well as store
the CRC as an “ID” for the object if needed later for
return value comparisons).
User defined characters’ CRC is requested as m, n = 4, 0.
Downloaded character sets are identified by integer
extending the existing code page selection as enumerated
in the select international character set (= select character
code table) command. The firmware standard list is
incrementally extended each time a new single or double
byte set is downloaded.
Single byte downloaded fonts are selected by
m = 3 and 0x40 <= n < 0x80.
Since there are only three double-byte character sets
supported, the value 0x80 / 0xA0 / 0xC0 selects the first,
second, third downloaded double byte font respectively. In
return, each downloaded double byte character band is
reported individually as 0xC0, 0xC1, 0xC2 ….for as many
bands as have been defined.
This command returns the state of occupancy of available
flash storage and user RAM. The printer response for each
item is a 4 byte header, 0x1D 0x97 nL nH (number of
bytes that follow in the response) and for each item a
4 byte structure: 1
st
m (type) byte, 2
nd
n index byte
followed by a 2 byte CRC in Lo Hi order of the data string
in that storage space.
The return for m = 0-2 is the header and one 4-byte item
giving remaining storage space in the CRC position in
Lo Hi order: 1D 97 4 0 m 0 fL fH, where f is the kBytes of
storage remaining. Note that RAM storage space is not
content typed, while available flash is statically divided
into logo, character set, and user data types. Change of the
divisions is possible via flash erasure and flash allocation
commands.
If the communication protocol is RS232 – Xon/Xoff, then
“X symbol substitution response” should be configured
with the setting communications parameters command
(US STX , 1F 02).