Tech FAQ

Some ANT products (specifically, the  CC257x) have ANT-FS client functionality embedded directly on the chip.  This includes the over the air ANT-FS protocol extension and the required file system utilities to manage stored data in non-volatile storage (EEPROM).  More details about this feature are available in the Integrated ANT-FS Control Document .

After receiving the download request, the client can update its beacon state to “Busy”, to let the host know that is processing the request.

The ANT-FS Technical Specification describes in detail the ANT-FS protocol and all the hand shaking and message formats involved.

The ANT-FS PC Tools package provides a PC implementation of both the host and client, which can be used to explore the functionality of ANT-FS as well as to aid with the development of your own devices.  Full source code is included. The libraries used for the development of these applications can also be used as the basis of custom PC applications that use ANT-FS.

The ANT-FS Embedded Client Reference Design includes sample C embedded code for the MSP430 implementing the ANT-FS client stack.

The ANT-FS Reference Design User Manual provides an overview of the usage and implementation details of the ANT-FS PC Tools, as well as the ANT-FS Embedded Client Reference Design.

Yes.  Both the client and host device are able to specify a maximum block size for data to be downloaded/uploaded.  The maximum block size indicates the maximum number of bytes that the device can transfer in a single block. If both devices specify a maximum block size, the smaller value will be used.

When both client and host device switch to authentication state, they will change their channel parameters (radio frequency and channel period) according to those specified in the LINK command sent by the host.  Check that both devices changed to the requested channel period, as a mismatch in this will result in unreliable communication.

The device type in the channel ID is an 8-bit identifier that denotes the type (class) of network device.  For example, it lets you know if a device is a heart rate monitor or a bike speed sensor.

The device type in the beacon is a 16-bit identifier that is assigned by the manufacturer, and generally, is used to distinguish between different products from that manufacturer.  As this field is manufacturer specific, ANT+ does not maintain a global list of beacon device types.

If this is a device implementing a file-based ANT+ device profile, the channel parameters and network key required to connect to it are specified in the corresponding device profile.

Otherwise, you will need to contact the manufacturer of the device.

ANT-FS can be used whenever you need to transfer files wirelessly between two devices.

Some common use cases are:
• Wireless firmware upgrades
• Transfer of configuration/settings
• Transfer of recorded data (either from a sensor or a data collection device)

“Authentication Rejected” means that the client device did not accept the request to authenticate. You can find more details on this on Section 5 and 12.5.2 of the "ANT-FS Technology" specification.  The client could be rejecting the authentication request for one of the following reasons:

• Incorrect authentication type requested: when implementing a host device, make sure to look at the contents of the beacon to determine the supported authentication types.
• Incorrect passkey: if the authentication type is passkey, make sure to enter the correct passkey.  The passkey is set by the manufacturer, and may be unique for each unit. Refer to the instructions of the manufacturer on how to obtain the passkey.
• Pairing timeout: if the authentication type is pairing, the client device prompts the user to accept/reject the pairing request, and will automatically reject the request if no response from the user is received within a given timeout.  Refer to the instructions of the manufacturer regarding how to handle pairing requests, as the mechanism may vary depending on the UI capabilities of the device.

The ANT-FS beacon contains a byte indicating the authentication methods supported by the device, as well as a flag to indicate whether pairing is enabled or not at the moment.

Also, if the device implements a file-based ANT+ device profile, the allowable authentication methods are specified in the corresponding device profile.