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AT42QT1085 [DATASHEET]
9625D–AT42–05/2013
6. Getting Started With the QT1085
6.1 Communication with the Host
The QT1085 uses an SPI bus to communicate with the host. See Section 5. on page 14 for more information.
6.2 Establishing Contact
The host should attempt to read the Information Block information to establish that the device is present and running
following power-up or a reset. The host should also check that there are no configuration errors reported.
6.3 Using the Object Protocol
The QT1085 has an object-based protocol that is used to communicate with the device. Typical communication
includes configuring the device, sending commands to the device, and receiving messages from the device. Refer to
the AT42QT1085 Protocol Guide.
The host must perform the following initialization so that it can communicate with the QT1085:
1. Read the start positions and sizes of all the objects in the QT1085 from the Object Table and build up a list of
these addresses.
2. Use the Object Table to calculate the report IDs so that messages from the device can be correctly interpreted.
6.4 Writing to the Device
See Section 5.2.3 on page 15 for information on the format of the SPI Write operation.
To communicate with the QT1085, write to the appropriate object:
To send a command to the device, write the appropriate command to the Command Processor T6 object (for
example, to send a reset, backup or calibrate command). Refer to the AT42QT1085 Protocol Guide for the full
list of available commands.
To configure the device, write to an object. For example, to configure the device power consumption write to
the global Power Configuration T7 object. Some objects are optional and need to be enabled before use.
Refer to the AT42QT1085 Protocol Guide for more information on the objects.
6.5 Reading from the Device
See Section 5.2.4 on page 16 for information on the format of the SPI Read operation.
