# GATT configuration parameters To configure the GATT server and client functions, use the server, client, and scan parameters. ## GATT server configuration parameters The two types of server configuration parameters used to [perform Bluetooth Low Energy GATT server functions](https://docs.qualcomm.com/doc/80-70018-13/topic/perform_ble_gatt_server_functions.html#perform-ble-gatt-server-functions) are: advertiser and server parameters. These configuration parameters are managed through `AdvertiserConfigFile.txt` and `ServerConfigFile.txt` files, respectively. `AdvertiserConfigFile.txt` The following table lists the possible values of each advertisement parameter in the `AdvertiserConfigFile.txt` file. | Parameters | Values | | --- | --- | | `TxPower` | **Legacy:**

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0: ADVERTISE_TX_POWER_ULTRA_LOW(-21)

1: ADVERTISE_TX_POWER_LOW(-15)

2: ADVERTISE_TX_POWER_MEDIUM(-7)

3: ADVERTISE_TX_POWER_HIGH(1)

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> **Extended:**
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0: TX_POWER_ULTRA_LOW =-21

1: TX_POWER_LOW =-15

2: TX_POWER_MEDIUM =-7

3: TX_POWER_HIGH = 1

| | `LegacyFlag` |

0: Use extended advertiser

1: Use legacy advertiser

| | `PeriodicFlag` |

0: Disable periodic advertiser

1: Enable periodic advertiser

| | `ConnectableFlag` |

0: Enable non-connectable advertiser

1: Enable connectable advertiser

| | `ScannableFlag` |

0: Enable non-scannable advertiser

1: Enable scannable advertiser

This value is applicable only to the extended advertisers. For the legacy advertisers, always set it to true.

| | `AnonymousFlag` |

0: Use the advertiser address in all PDUs

1: Don’t use the advertiser address in PDUs

| | `IncludePower` |

0: Don’t include Tx power in the extended header

1: Include Tx power in the extended header

| | `PrimaryPhy` |

1: 1 M-PHY

3: Low Energy (LE) coded PHY

| | `SecondaryPhy` |

1: 1 M-PHY

2: 2 M-PHY

3: LE coded PHY

| | `Interval` |

160: Minimum advertisement interval (100 ms)

16777215: Maximum advertisement interval (10,485 s)

| | `TimeOutLegacy` |

0: Minimum possible value

180000: Maximum possible timeout value in ms

| | `AdvertiseMode` |

0: Low-power mode

1: Balanced mode

2: Low latency mode (used for legacy)

The advertisement interval is selected based on the advertiser mode as follows:

Low-power mode: 1 s advertisement interval

Balanced mode: 250 ms advertisement interval

Low latency mode: 100 ms advertisement interval

| | `BLEBtName` | The name to be displayed for that particular advertiser set. | The following snippet shows an example of an advertisement set: *******************AdvertisingSet1*************** TxPower:1 LegacyFlag:1 PeriodicFlag:0 ConnectableFlag:1 ScannableFlag:1 AnonymousFlag:0 IncludePower:1 PrimaryPhy:1 SecondaryPhy:1 Interval: 320 TimeOutLegacy:0 AdvertiseMode:1 BLEBtName:Adv1 Copy to clipboard `ServerConfigFile.txt` The following table lists the possible values of each service parameter in the `ServerConfigFile.txt` file. | Parameter | Description | | --- | --- | | `service uuid` | The service ID. A server can have multiple services. | | `characteristic uuid` | The ID of the characteristic. A service can have multiple characteristics. A characteristic can have properties and permissions. | | `characteristic properties` | The properties of the characteristic.

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> Combine the following characteristic properties with a logical OR argument, as required:
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> PROPERTY_BROADCAST = 0x01;
> PROPERTY_READ = 0x02;
> PROPERTY_WRITE_NO_RESPONSE = 0x04;
> PROPERTY_WRITE = 0x08;
> PROPERTY_NOTIFY = 0x10;
> PROPERTY_INDICATE = 0x20;
> PROPERTY_SIGNED_WRITE = 0x40;
> PROPERTY_EXTENDED_PROPS = 0x80;
> Copy to clipboard | | `characteristic permissions` | The permissions of the characteristic.

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>
> Combine the following characteristic permissions with a logical OR argument, as required:
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> PERMISSION_READ = 0x01;
> PERMISSION_READ_ENCRYPTED = 0x02;
> PERMISSION_READ_ENCRYPTED_MITM = 0x04;
> PERMISSION_WRITE = 0x10;
> PERMISSION_WRITE_ENCRYPTED = 0x20;
> PERMISSION_WRITE_ENCRYPTED_MITM = 0x40;
> PERMISSION_WRITE_SIGNED = 0x80;
> PERMISSION_WRITE_SIGNED_MITM = 0x100;
> Copy to clipboard | | `descriptor uuid` | The ID of the descriptor. A characteristic can have multiple descriptors. A descriptor can have permissions. | | `descriptor permissions` | The permissions of the descriptor. | The following snippet shows an example of a service in the GATT server. **************Server1************* Service1:[service uuid],[characteristic uuid],[characteristic properties],[characteristic permissions],[descriptor uuid],[descriptor permissions] Service1:00001200-0000-1000-8000-00805f9b34fb, 00001101-0000-1000-8000-00805f9b34fb,26,31,00002a06-0000-1000-8000-00805f9b34fb,17 ManufacturerId:0 ManufacturerData:AAAA **************End of service************* Copy to clipboard ## GATT client configuration parameters The following table lists the connection parameters used to configure the GATT client. | Parameter | Values | Notes | | --- | --- | --- | | `isAuto` |

0: Connects directly

1: Connects automatically as soon as a remote device is available

| If this parameter is set to `1`, ensure that the devices are bonded for auto connection. | | `isOpportunistic` |

0: Connects directly

1: Provides the handle if it’s already connected based on the address and transport

| If this parameter is set to `1`, it doesn’t start the connection if it’s not already present. | | `Tx_Phy` |

1: 1 M-PHY

2: 2 M-PHY

4: LE coded PHY

7: All PHYs

| ̶̶ | | `Rx_Phy` |

1: 1 M-PHY

2: 2 M-PHY

4: LE coded PHY

7: All PHYs

| ̶̶ | | `Phy_Opt:00` |

0: Host preferred coding scheme

1: Use S = 2 (500 Kbps) coding scheme

2: Use S = 8 (125 Kbps) coding scheme. Use it only when the PHY is LE coded.

| ̶̶ | | `Mtu_Size` |

The minimum value is 23.

The maximum value is 512.

| ̶̶ | ## Scan settings The following table lists the scan settings used to configure the GATT client. | Scan types | Values | Notes | | --- | --- | --- | | `1: Scan_mode` |

-1: Opportunistic mode

0: Low-power mode

1: Balanced mode

2: Low latency mode

**Regular scan:**

0: Scan window (512 ms); scan interval (5120 ms)

1: Scan window (1024 ms); scan interval (4096 ms)

2: Scan window (4096 ms); scan interval (4096 ms)

**Batch scan:**

0: Scan window (1500 ms); scan interval (150,000 ms)

1: Scan window (1500 ms); scan interval (15,000 ms)

2: Scan window (1500 ms); scan interval (5000 ms)

| ̶̶ | | `2: CallbackType` |

1: Initiates a callback to all the matched advertisements

2: Initiates a callback to the first matched advertisement

4: Initiates a callback when a device detected earlier stops sending advertisements.

| ̶̶ | | `3: ResultType` |

0: Provides full scan results that have the device, RSSI, advertising data, scan response and, scan timestamps.

1: Provides scan results that have the device, RSSI, and scan timestamps.

| ̶̶ | | `4: ScanPhy` |

1: 1 M-PHY

3: LE coded PHY. Use it for extended scanning only.

255: All supported PHYs

| Currently, it’s hard coded to 255 in the application code. | | `5: Legacy` |

True: Legacy scanning

False: Extended scanning

| ̶̶ | | `6: ReportDelay` |

0: Deliver reports immediately

>0: Accumulate scan results and deliver them after the delay mentioned (in ms) or if buffers are full (batch scan).

| ̶̶ | | `7: MatchMode` |

1: Aggressive match mode. The hardware finds a match even with feeble signal strength.

2: Sticky match mode. It requires a higher threshold of signal strength.

| ̶̶ | | `8: NumOfAdvMatches` |

1: Matches one advertisement per filter

2: Matches few advertisements according to availability of hardware resources

3: Matches as many advertisements as the hardware allows

| ̶̶ | Last Published: Apr 02, 2025 [Previous Topic Perform Bluetooth Low Energy GATT client functions](https://docs.qualcomm.com/bundle/publicresource/80-70018-13/topics/perform_ble_gatt_client_functions.md) [Next Topic Advanced Audio Distribution Profile](https://docs.qualcomm.com/bundle/publicresource/80-70018-13/topics/set-up-a2dp.md)