ADIS16IMU5SLASHPCBZ datasheet(20/46 Pages) AD

20 / 46 page

Data Sheet

ADIS16575/ADIS16576/ADIS16577

THEORY OF OPERATION

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Rev. 0 | 20 of 46

READING SENSOR DATA

Reading a single register requires two 16-bit cycles on the SPI:

one to request the contents of a register and another to receive

those contents. The 16-bit command code (see Figure 53) for a

read request on the SPI has three parts: the read bit ( R/W = 0),

either address of the register, [A6:A0], and eight don’t care bits,

[DC7:DC0]. Figure 52 shows an example that includes two register

reads in succession. This example starts with DIN = 0x0C00 to re-

quest the contents of the Z_GYRO_LWR register, and follows with

0x0E00 to request the contents of the Z_GYRO_UPR register. The

sequence in Figure 52 also shows a full duplex mode of operation,

meaning that the ADIS16575/ADIS16576/ADIS16577 can receive

requests on DIN while also transmitting data out on DOUT within

the same 16-bit SPI cycle.

Figure 52. SPI Read Example

Figure 54 shows an example of the four SPI signals in a repeating

pattern when reading the PROD_ID register (see Table 136) in a

repeating pattern. This pattern can be helpful when troubleshooting

the SPI setup and communications because the signals are the

same for each 16-bit sequence, except during the first cycle.

Note that the read and write functions of the SPI are always 16 bits

long. The only exception is the burst read function described in the

Burst Read Function section.

Figure 53. SPI Communication Bit Sequence

Figure 54. SPI Signal Pattern, Repeating Read of the PROD_ID Register

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