BTM411 Series Bluetooth Module
Overview
The BTM411 Bluetooth module from Laird Connectivity has been designed to meet the needs of developers who wish to add robust short range Bluetooth data connectivity to their products. They are based on the market leading Cambridge Silicon Radio BC04 chipset providing exceptionally low power consumption with outstanding range. They support the latest Bluetooth Version 2.1 Specification providing the important advantage of Secure Simple Pairing which improves security and enhances the ease of use for end customers. BTM411 variants available.
Note: The BTM410 has reached end of production and is available on a limited basis only. Only the BTM410 part numbers are affected. Find the End of Life Announcement in the Documentation tab below.
Specifications
FCC/IC & CE - Limited Modular Approval
UART: Greater than 300 Kbps
GPIO (8 lines shared)
Idle (sleep) < 1 mA
Voice over SCO via a PCM interface
I/O: 1.7 V to +3.6 V (independent of VCC)
| Antenna Options | BLE Services | Bluetooth Version | Chipset (Wireless) | Compliance | Connector Type | Data Rate | Development Kit Contents | Dimension (Height - mm) | Dimension (Length - mm) | Dimension (Width - mm) | Frequency | Frequency Range (Max) | Frequency Range (Min) | Input Power | Logical Interfaces | Max Transmit Power | Power Consumption | Protocols | Range | Receive Sensitivity | Software | Weight | Wi-Fi Coexistence | Wireless Specification | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| BTM411 | Integrated Antenna | GAP | v2.1 + EDR | CSR BC04 | FCC / IC / CE | SMT | 2.1 MBps | Development board and software tools | 3.4 mm | 22 mm | 12.5 mm | 2.4 GHz | 2.480 GHz MHz | 2.402 GHz MHz | 3.0 – 3.3V | UART | +4 dBm | 32mA | AT Command Set | Up to 30 meters | -84 dBm | Terminal Software | .105 oz (3 g) | 2 wire and 3 wire schemes supported | Bluetooth v2.1 + EDR |
| Antenna Options | BLE Services | Bluetooth Version | Chipset (Wireless) | Compliance | Connector Type | Data Rate | Development Kit Contents | Dimension (Height - mm) | Dimension (Length - mm) | Dimension (Width - mm) | Frequency | Frequency Range (Max) | Frequency Range (Min) | Input Power | Logical Interfaces | Max Transmit Power | Power Consumption | Protocols | Range | Receive Sensitivity | Software | Weight | Wi-Fi Coexistence | Wireless Specification | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| BTM411-03 | Integrated Antenna | GAP | v2.1 + EDR | CSR BC04 | FCC / IC / CE | SMT | 2.1 MBps | Development board and software tools | 3.4 mm | 22 mm | 12.5 mm | 2.4 GHz | 2.480 GHz MHz | 2.402 GHz MHz | 3.0 – 3.3V | UART | +4 dBm | 32mA | AT Command Set | Up to 30 meters | -84 dBm | Terminal Software | .105 oz (3 g) | 2 wire and 3 wire schemes supported | Bluetooth v2.1 + EDR |
| Antenna Options | BLE Services | Bluetooth Version | Chipset (Wireless) | Compliance | Connector Type | Data Rate | Development Kit Contents | Dimension (Height - mm) | Dimension (Length - mm) | Dimension (Width - mm) | Frequency | Frequency Range (Max) | Frequency Range (Min) | Input Power | Logical Interfaces | Max Transmit Power | Power Consumption | Protocols | Range | Receive Sensitivity | Software | Weight | Wi-Fi Coexistence | Wireless Specification | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| BTM411-03-T/R | Integrated Antenna | GAP | v2.1 + EDR | CSR BC04 | FCC / IC / CE | SMT | 2.1 MBps | Development board and software tools | 3.4 mm | 22 mm | 12.5 mm | 2.4 GHz | 2.480 GHz MHz | 2.402 GHz MHz | 3.0 – 3.3V | UART | +4 dBm | 32mA | AT Command Set | Up to 30 meters | -84 dBm | Terminal Software | .105 oz (3 g) | 2 wire and 3 wire schemes supported | Bluetooth v2.1 + EDR |
| Antenna Options | BLE Services | Bluetooth Version | Chipset (Wireless) | Connector Type | Data Rate | Frequency | Frequency Range (Max) | Frequency Range (Min) | Logical Interfaces | Max Transmit Power | Protocols | Range | Receive Sensitivity | Software | Wi-Fi Coexistence | Wireless Specification | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| DVK-BTM411 | Integrated Antenna | GAP | v2.1 + EDR | CSR BC04 | USB Pluggable | 2.1 MBps | 2.4 GHz | 2.480 GHz MHz | 2.402 GHz MHz | USB | +4 dBm | AT Command Set | Up to 30 meters | -84 dBm | Terminal Software | 2 wire and 3 wire schemes supported | Bluetooth v2.1 + EDR |
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Documentation
BT 2.1 - SSP initiated by a BTM module
This article is designed to illustrate the process of Simple Secure Pairing (SSP) when initiated from a BTM module. Introduced in Bluetooth v2.1, SSP creates a bond in a very different way than the legacy PIN pairing many users are familiar with. This is demonstrated both for security level 2 (default) and security level 3.
Security Level = 2
Assumptions:
peer device is BT2.1 (supporting secure simple pairing)
security level of BTM device is
security level of peer device is
the pairing initiating device is aware of the peer device's Bluetooth Device Address
Note: Connections in Bluetooth v2.1 are always encrypted.
Figure 1: BTM vs BTM
Figure 2: BTM vs PC
Security Level = 3
Assumptions:
peer device is BT2.1 (supporting secure simple pairing)
at least one device with security level = 3 (MITM protection / authentication enabled)
the pairing initiating device is aware of the peer device's Bluetooth Device Address
Remarks:
Connections with BT2.1 are always encrypted
"MITM" = Man-In-The-Middle. "MITM protection" means "protection against a MITM attack".
MITM protection is equivalent with authentication
Figure 3: BTM vs BTM, security level 3
Figure 4: BTM vs PC, security level 3
Is Sniff Mode supported only as a Slave or as a master or Slave in the BTM41x and BTM51x modules?
Based on a scenario between two BTM41x modules (referenced in the BTM41x Low Power Modes Application Note), the role of a device (master/slave) does not have an impact on sniff mode. In the scenario, sniff mode requests were accepted with requested parameters and were applied on the link, regardless of which end they were initiated from. Thus, at least one end must actively request sniff mode at some point after a connection has been created and the other end must at least not reject sniff mode. If the other end requests sniff mode as well, then the parameters of the most recent request will apply to the link.
Again, this has been done between two BTM41x modules. The relevant source code from this scenario was later ported across to the BTM51x. Confirming tests and measurements have not been carried out on the BTM51x. However, there is no obvious reason why it should behave differently on the BTM51x.
Please note that sniff configuration refers to Rfcomm based links :SPP, HSP, HFP. For AVRCP/A2DP there are some a default setting.
It should be possible to evaluate if a remote device requests sniff mode: Disable local sniff mode by setting Sniff parameters to zero (S561- S564, by default these are zero) and while in a connection check ATi13 repeatedly. If the response is ‘1: b,c,d,e’ then sniff mode has been entered, caused by the remote end. The resulting sniff parameters (b,c,d,e) are likely to be the ones requested by the remote end.
What is the throughput of your bluetooth modules with the embedded AT command interface?
Our fully-embedded modules have a throughput of around 300-360 kbps. They have an on-board Bluetooth stack and do all of the Bluetooth processing themselves. Bluetooth 2.1 + EDR has a practical transfer rate of 2.1 Mbit/s, but this is not possible on a small embedded module that does not have a powerful PC-type processor.