20
5 Mode Select—15h
Command Description
The
MODE SELECT
command allows the initiator to change device parameters of the library.
An initiator uses these parameters to configure the library after power-up or a bus
device reset message. Library parameters that can be set with
MODE SELECT
are element
addresses, enabling or disabling the bar code reader, and enabling or disabling bar
code checksum checking.
If requested, by setting the SP (Save Pages) bit in the command descriptor, the library
saves all mode parameters to nonvolatile RAM and automatically reloads them when it
initializes, following a reset or power-up.
Any changed parameters apply to all initiators in a multi-initiator environment. If mode
parameters are changed, the library generates a
UNIT ATTENTION
to all initiators except the
one that issued the
MODE SELECT
command, with sense information to indicate that mode
parameters have changed.
Note:
Before issuing any
MODE SELECT
command, issue a
MODE SENSE
command
with the Page Code field set to 3Fh, so the library returns all mode
pages, and the Page Control field set to 01h, so the library indicates
which fields are changeable.
To change parameter values, send a
MODE SELECT
command, followed by a mode
parameter list in the Data Out phase. The table below shows the CDB for the
MODE SELECT
command. Values and meanings of field names in bold are further described in Table
5-2. The mode parameter is discussed on page 21 and in
Chapter 6. Mode Sense—1Ah
.
Table 5-1: Mode Select Command—15h
00
Operation code—15h
Byte
Bit
0
1
2
3
4
5
6
7
01
Logical Unit Number—0h
PF
Reserved
SP
02
Reserved
03
Reserved
04
Parameter List Length
05
0
0
Reserved
0
0
