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www.lairdtech.com
Laird Technologies
BTM520/521
Bluetooth
®
Multimedia Plus Module
CONFIGURING
THE BTM520/521
Table 3-1: S-Register List
REGISTER
DEFAULT
RANGE
COMMENT
S0
1
-1..15
Number of RING indication before automatically answering an incoming
connection. A value of 0 disables autoanswer. If -1, then autoanswer on one
RING and do NOT send RING/CONNECT response to the host. This emulates a
serial cable replacement situation
Setting values >= 0, resets S Register 504 to 0 and <0 forces 504 to 1.
If S0 <> 0 and S100 <> 0 then S0 must be < S100. If a value is entered which
violates this rule, then ERROR 29 is sent in response.
If S504 =1 then this register will return -1, regardless of the actual value
stored in non-volatile memory.
S2
0x5E
0x20..0x7E
Escape sequence character. It is not ‘+’ by default as a
Bluetooth
®
serial link
can be used to connect to a mobile phone which exposes an AT command
set, which will in turn use ‘+’ as default. So if both used ‘+’ there will be
confusion. 0x5e is the character ‘^’.
S12
100
40..5000
Escape sequence guard time in milliseconds, with a granularity of 20ms. New
values are rounded down to the nearest 20ms multiple
S100
15
0..15
Number of RING indications before an auto disconnection is initiated. A value
of 0 disables this feature.
If S0 <> 0 and S100 <> 0 then S0 must be < S100. If a value is entered which
violates this rule, then ERROR 29 is sent in response.
S101
$1101
0..$ffff
UUID of default SPP based profile when not specified explicitly in the ATD
command.
S102
1
1..0x7FF
Defines a set of bits masks for enabling profile servers. Values can be ORed.
0x001 is Serial Port Profile
0x080 is A2DP
0x100 is AVRCP
S103
1
1..7
Boot Mode on cold boot.
S126
?
0 .. 0xFFFF
Primer for changing to Multipoint mode
S127
?
0 .. 0xFFFF
0x100 for At mode
0x200 for Multipoint mode
Other values are reserved
S300
1
0..2
Set A2DP role:
0 is feature not set
1 is A2DP Sink (default)
2 is A2DP Source
S301
1
0..2
Set AVRCP role:
0 is feature disabled
1 is Control (CT) (default)
2 is Target (TG)
8. ATSn=m {Set S Register}
As with modems, the Bluetooth module employs a concept of registers which are used to store
parameters, such as escape sequence character, inquiry delay time etc, as listed in detail below.
The value part ‘m’ can be entered as decimal or hexadecimal. A hexadecimal value is specified via
a ‘$’ leading character. For example $1234 is a hexadecimal number.
When S register values are changed, the changes are not stored in non-volatile memory UNTIL
the AT&W command is used. Note that AT&W does not affect S registers 520 to 525 or 1000
to 1010 as they are updated in non-volatile memory when the command is received.
