Xsens MTi 1 Series, Руководство пользователя

Страница: 22 / 101

MTi 1-series User Manual
Xsens MTi User Manual Repository Datasheet
Copyright © 2021 Xsens Page 19
of the protocol by writing the Protocol Configuration. The Master can also read the Protocol
Configuration to check current behavior, and get protocol information.
Note: Both the Measurement Pipe and the Notification Pipe have limited sizes and can therefore
only contain a limited number of (reduced) Xbus messages. The amount of messages that can
be contained in the pipes depends on the size of the individual messages. Both pipes act as a
First-In-First-Out (FIFO) buffer: When reading from either pipe, the oldest message in the pipe
will be read first. Once the pipe is full, a newly produced message will be discarded by the MTi
1-s and a (reduced Xbus) error message (data overflow, 0x42 0x01 0x29 0x95) will be added to
the Notification Pipe. It is therefore important for the host to read out new messages in time,
such that the pipe will not fill up, resulting in lost measurement data or notifications.
For best practices for I
2
C and SPI communication, please see BASE: Best practices I
2
C and SPI
for MTi 1-series
Data flows within MTSSP
Data ready signal
The Data Ready Signal (DRDY) is a notification line driven by the module. Its default behavior is
to indicate the availability of new data in either the Notification or the Measurement pipe. By
default, the line is low when both pipes are empty, and will go high when either pipe contains an
item. As soon as the Master has read all pending messages, the DRDY line will go low again.
The Master can change the behaviour of the DRDY signal using the Procotol Configuration.
Please refer to the description of the ConfigureProtocol opcode (#List of defined opcodes) for
more information.
Opcodes
The Master starts each transfer with an opcode. The opcode determines the type of the