Bluetooth LE and LTE Cat.1 Combo

Last Updated on : 2024-06-04 08:28:56download

This topic describes the commands specific to the Bluetooth Low Energy (LE) and LTE Cat.1 combo protocol.

Product authorization

The Bluetooth LE chip stores authorization information. When connected to an LTE Cat.1 module, the Bluetooth LE module transmits activation and authorization data to the LTE Cat.1 module via UART communication. The LTE Cat.1 module is not allowed to proactively bind with and unbind from the cloud. When the Bluetooth LE module has been unbound, it should notify the LTE Cat.1 module of its unbinding.

This block diagram illustrates the interaction between the Bluetooth LE module and the LTE Cat.1 module.

Query module’s unique identifier (0xD0 00)

The Bluetooth LE module sends the following data.

Field	Bytes	Description
Header	2	0x55aa
Version	1	0x03
Command	1	0xD0
Data length	2	0x0001
Data	1	Subcommand: 0x00
Checksum	1	Start from the header, add up all the bytes, and then divide the sum by 256 to get the remainder.

The module returns the following data.

Field	Bytes	Description
Header	2	0x55aa
Version	1	0x00
Command	1	0xD0
Data length	2	N
Data	1	Subcommand: 0x00
	1	`result`: `0`: Success. `Other values`: Failure. The payload is invalid if the operation fails.
	1	The binding status of the module. `0`: Unbound. `1`: Bound.
	1	`type`: The module type. Only `2` and `3` are applicable currently. `1`: NB-IoT `2`: Wi-Fi `3`: LTE Cat.1 `4`: Zigbee `5`: Bluetooth LE
	N	XXX (The unique identifier of the module)
Checksum	1	Start from the header, add up all the bytes, and then divide the sum by 256 to get the remainder.

Sync authorization information (0xD0 01)

The Bluetooth LE module sends the following data.

Field	Bytes	Description
Header	2	0x55aa
Version	1	0x03
Command	1	0xD0
Data length	2	N
Data	N	Subcommand: `0x01` The encryption method. `0x00`: AES-CBC `0x01`: AES-CCM `0x02`: Other Random number (16 bytes) {“uuid”:“xxxx”, “auth_key”:“xxxx”, “psk_key”:“xxxx”} `uuid`, `auth_key`, and `psk_key`
Checksum	1	Start from the header, add up all the bytes, and then divide the sum by 256 to get the remainder.

The module returns the following data.

Field	Bytes	Description
Header	2	0x55aa
Version	1	0x00
Command	1	0xD0
Data length	2	0x0002
Data	35	Subcommand: `0x01` `result`: `0`: Success. `Other values`: Failure. The encryption method. `0x00`: AES-CBC `0x01`: AES-CCM `0x02`: Other Use `HMAC-SHA256` to encrypt the `key` with both the random number and shared key. `key_len` is 32 bytes.
Checksum	1	Start from the header, add up all the bytes, and then divide the sum by 256 to get the remainder.

Sync activation information (0xD0 02)

The Bluetooth LE module sends the following data.

Field	Bytes	Description
Header	2	0x55aa
Version	1	0x03
Command	1	0xD0
Data length	2	N
Data	1 + N	`Subcommand: 0x02` { “devId”:“xxxx”, “localKey”:“xxxx”, “secKey”:“xxxx”, “env”:“xxxx”, “region”:“xxxx” } The data is encrypted with AES. The algorithm depends on the field of the encryption method. `Key`: the first 16 bytes of the shared key. `iv`: all zeros. Padding: The data must be padded to ensure that its total length is an integral multiple of 16.
Checksum	1	Start from the header, add up all the bytes, and then divide the sum by 256 to get the remainder.

The module returns the following data.

Field	Bytes	Description
Header	2	0x55aa
Version	1	0x00
Command	1	0xD0
Data length	2	1
Data	1 (Subcommand)	0x02
	Result	`0` indicates the LTE Cat.1 module has received activation information and is currently activating. You can verify the activation result by checking the network status in basic services.
Checksum	1	Start from the header, add up all the bytes, and then divide the sum by 256 to get the remainder.

Get the key (0xD0 03)

The Bluetooth LE module sends the following data.

Field	Bytes	Description
Header	2	0x55aa
Version	1	0x03
Command	1	0xD0
Data length	2	0x42 (66)
Data	66	Subcommand: `0x03` Curves for elliptic curve cryptography (ECC). `1`: secp192r1 `2`: secp224r1 `3`: secp256r1 `4`: secp256k1 The public key of the MCU: 64 bytes
Checksum	1	Start from the header, add up all the bytes, and then divide the sum by 256 to get the remainder.

The module returns the following data.

Field	Bytes	Description
Header	2	0x55aa
Version	1	0x00
Command	1	0xD0
Data length	2	0x42 (66)
Data	66	Subcommand: `0x03` Curves for elliptic curve cryptography (ECC). `1`: secp192r1 `2`: secp224r1 `3`: secp256r1 `4`: secp256k1 The public key of the module: 64 bytes
Checksum	1	Start from the header, add up all the bytes, and then divide the sum by 256 to get the remainder.

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