Specifications

I2S Audio Commands
Rev. 8 May.12 Proprietary and Confidential 177
!AVTXPCMIIRFLTR
Supporting chipsets (voice-
enabled devices only):
• MDM8200A (min f/w rev:
T3_0_1_5)
Note: For MDM6200, MSM6290,
and QSC6270, see !AVTXPCMI-
IRFLTR on page 156.
Set/report the Tx PCM IIR filter parameters
The modem has a multi-stage PCM (Pulse Code Modulation) IIR (Infinite Impulse
Response) filter. Use this command to set parameters for each stage of the specified
profile.
See “!AVRXPCMIIRFLTR” on page 170 for a description of using the filters.
The change takes effect immediately for the specified profile.
Usage:
• Execution (Enable/disable IIR):
AT!AVTXPCMIIRFLTR=<profile>, 0, <IIR_stages>
Response: OK
Purpose: Set the number of stages for the filter.
• Execution (Set stage coefficients):
AT!AVTXPCMIIRFLTR=<profile>, <stage>, <b0>, <b1>, <b2>,
<a1>, <a2>
Response:
OK
Purpose: Set the parameters for a specific stage.
• Query (IIR state):
AT!AVTXPCMIIRFLTR?<profile>, 0
Response: <enabled>,<IIR_stages>
OK
Purpose: Indicate whether IIR is enabled, and (if enabled) the number of IIR
filter stages.
• Query: AT!AVTXPCMIIRFLTR?<profile>, <stage>
Response:
<b0>,<b1>,<b2>,<a1>,<a2>
OK
or ERROR (if <stage> is greater than the number of stages defined
for the profile)
Purpose: Return the filter coefficients for a specific stage. (Note: The coeffi-
cients are returned even if IIR is currently disabled.)
Parameters:
<profile> (Voice profiles)
• Valid range: 0–2 (See !AVSETDEV on page 173 for available profiles.)
<IIR_stages> (Enable IIR and set number of stages, or disable IIR):
• 0=Disable IIR
• 1–10=Enable IIR with this number of stages
<stage> (IIR stage)
• 1–10=Stage to be configured
<a1> (IIR filter coefficient a1)
<a2> (IIR filter coefficient a2)
• Signed hexadecimal
• 0x00000000–0xFFFFFFFF
<b0> (IIR filter coefficient b0)
<b1> (IIR filter coefficient b1)
<b2> (IIR filter coefficient b2)
• Signed hexadecimal
• 0x00000000–0xFFFFFFFF
Table 8-2: I2S audio command details (Continued)
Command Description