Xsens MTi 1 Series, Руководство пользователя

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MTi 1-series User Manual
Xsens MTi User Manual Repository Datasheet
Copyright © 2021 Xsens Page 27
give the Slave time to select the data it must send for the remainder of the transfer. Both Master
and Slave are free to choose the value of the fill words, and the receiving end should ignore their
value. However, the first 4 bytes transmitted by the MTi 1-series module (Slave) are always
0xFA, 0xFF, 0xFF, 0xFF.
Following the first four words are the actual data of the transfer. It is the responsibility of the
Master to determine how many bytes it must transfer. For reading the Notification- and
Measurement Pipes, the number of bytes the Master must read depends on the size of the
pending message. In order to determine the correct number of bytes, the Master should first
read the Pipe Status to obtain the sizes of the pending messages.
Timing
The table below and figure specify the timing constraints that apply to the SPI transport layer.
The Master must adhere to these constraints.
SPI timing
Symbol Parameter Unit Min Max
T1 Slave select to first complete word
delay
μ
s 4
T2 Byte time μ s 4
T3 Consecutive SPI transfer guard
time
μ
s 3
Max SPI bitrate Mbit 2
SPI timing
UART half-duplex