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www.lairdtech.com
Laird Technologies
BTM520/521
Bluetooth
®
Multimedia Plus Module
CONFIGURING
THE BTM520/521
3.1.5 Send remote control command
AT+AVC<operation_id
hex
>,<button_state>
Send a remote control command to a connected AVRCP target. Internally, a PASS
THROUGH command is created and sent to the PANEL subunit of the AVRCP target.
<operation_id
hex
> is the value for the actual remote control command. Valid values are
specified in Table 3 8. Some Operation IDs can be replaced by mnemonics, see Table 3 8.
<button_state> represents “Button pushed” (=0) or “Button released” (=1)
If <button_state> is not specified, two PASS THROUGH commands, each with
button_state=0 and button_state=1 will be created and sent consecutively.
The “OK” response is sent immediately on receipt of AT+AVC command. On command
completion, an unsolicited message will be sent to the host in the form “AVPTC n
<bd_addr> <button_state>”. AVPTC means “AVrcp Pass Through Confirmation”.
Parameter n indicates the command status:
‘n’=0: successful, command confirmation received from target
‘n’=1: timeout, target has not sent confirmation within the specified maximum time
‘n’=2: all other unsuccessful outcomes
Parameters:
<operation_id
hex
>
(mandatory):
see Table 3 8
<button_state>
(optional) :
‘0’ - Button pushed
‘1’ - Button released
Response:
<cr,lf>OK<cr,lf> (immediately)
And:
<cr,lf>AVPTC n <operation_id
hex
> <button_state><cr,lf>
(after command completion)
If status n indicates an unsuccessful outcome,<operation_id
hex
> and <button_state>
are omitted.
3.2 AVRCP – Target (TG)
This section describes AT Commands and S registers when BT-MM+ is configured as an AVRCP
Target (S301=2). In this mode, BT-MM+ supports one subunit PANEL (see [5]).
3.2.1 Incoming AVRCP Connection Request
An incoming AVRCP connection request is accepted automatically if a valid link key for
the paging device exists. If no link key is available, Secure Simple Pairing (SSP, BT2.1)
or legacy pairing (BT2.0 or earlier) is carried out, depending on the Bluetooth Version
of the paging device.
After an AVRCP connection has been established, the module remains in AT command
mode. S Register 531 is ignored for AVRCP connections.
3.2.2 UNIT INFO Response
It is mandatory to respond to a UNIT INFO command if configured as AVRCP target.
Required response parameters are IEEE Company ID and a Unit Type.
The IEEE Company ID is a 24 bit integer which can be set via new S register 303.
In the current revision of BT-MM+ firmware, subunit “Panel” (=0x09) will be returned
always. Values of unit/subunit types are outlined in Table 3 9.
3.2.3 SUBUNIT INFO Response
It is mandatory to respond to a SUBUNIT INFO command if configured as AVRCP target.
Required response parameters are Subunit type and MaxSubUnitId.
Subunit type will always be returned as 0x09 (Panel).
MaxSubUnitId will always be returned as 0x00 (only one subunit exists, which is panel)
