SCA3000 Series
4.1.3.2 Example of decremented register read
Figure 8 presents a decremented read operation where the content of four output registers is read
by one SPI frame. After normal register addressing and one register content reading, the µC keeps
the CSB line low and continues supplying the SCK pulses. After every 8 SCK pulses, the output
data address is decremented by one and the previous acceleration output register's content is
shifted out without parity bits. The parity bit in Figure 4 is calculated and transferred only for the first
data frame. From the X_LSB register address, the SCA3000 jumps to Z_MSB. Decremented
reading is possible only for registers X_LSB ... Z_MSB.
Figure 8. An example of decremented read operation.
4.1.3.3 Example of ring buffer read
An example of output ring buffer read by one SPI frame (ring buffer data length 8 bits) is presented
in Figure 9. The whole ring buffer read procedure is very similar to decremented read described
above. The output ring buffer is addressed (register name BUF_DATA). The SCA3000 sensor
continues shifting out the ring buffer content as long as µC continues supplying the SCK pulses.
Figure 9. An example of output ring buffer read operation.
4.1.4 Multiple slave devices in SPI bus
In SCA3000-D03 and SCA3000-L01 sensors both the SPI and the I2C communication blocks are
enabled. In order to prevent possible communication interference in SPI bus usage, it is strongly
recommended that the I2C communication block is disabled when SCA3000-D03 or SCA3000-L01
are used in SPI bus where other slave devices are connected as well. The I2C communication
block disabling should be done always right after the sensor is power up.
If SCA3000-D03 and SCA3000-L01 are used in point to point SPI bus (no other slave devices), the
I2C communication disabling can be ignored.
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