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 26
data from the beginning.
SPI
The MTi 1-series module acts as an SPI Slave. The User of the MTi 1-series module is the SPI
Master.
SPI Configuration
The MTi 1-series supports 4-wire mode SPI. The four lines used are:
Chip Select (SPI_nCS)
Serial Clock (SPI_SCK)
Master data in, slave data out (SPI_MISO)
Master data out, slave data in (SPI_MOSI)
The module uses SPI mode 3: It captures data on the rising clock edge, and it
latches/propagates data on the falling clock edge. (CPOL=1 and CPHA=1). Data is clocked-out
MSB first. The module uses an 8-bit data format.
Data transfer
The module uses a single type of SPI transfer for all communications. The below figure depicts
this basic transfer.
SPI basic transfer
The Master starts a transfer by pulling the SPI_nCS low, in order to select the Slave. The Master
must keep the SPI_nCS line low for the duration of the transfer. The Slave will interpret the rising
edge of the SPI_nCS line as the end of the transfer. The Master places the data it needs to
transmit on the SPI_MOSI line. The Slave will place its data on the SPI_MISO line.
The Master first transmits the opcode. The opcode determines what kind of data the Master
transmits, and what kind of data the Master wants to read from the Slave (see #MTSSP). The
second-to-fourth byte the Master transmits are the fill words. These fill words are needed to