MA700GQ-P Datasheet, PDF (8/15 Pages) MPS Industries, Inc. – Angular Sensor for Position Control with Side-Shaft Positioning Capability

MA700
Angular Sensor for Position Control with
Side-Shaft Positioning Capability
8. Digital Signal Conditioning
Digital Filtering
Advanced digital filtering allows improving the
resolution without adding latency. The principle is to
measure the rotation speed over the last 512 data points
in addition to the angular position to provide an
evaluation of the present position with the best possible
accuracy. This principle gives a lag-free position at
constant speed.
Zero setting
The zero position of the MagAlpha, , can be
programmed with 12 bit of resolution. The angle
streamed out, , is given by:
,
where is the raw angle, out of the front-end. The
parameter Z(11:0), which is 0 by default, determines
(see Table 18). This setting is valid for all output
formats: SPI, ABZ and UVW.
TABLE 11 ZERO POSITION
Z(11:0)
0
1
…
4095
Zero position (deg)
0
0.088
…
359.912
Rotation direction
Looking at the MagAlpha top, the angle increases
when the magnetic field rotates clockwise.
9. Programming the MA700
The MA700 incorporates 3 programmable registers.
Each register has 8 bit of memory. When the MA700 is
powered up, each of these 3 x 8 bit of memory are set
to zero, unless the register was previously stored in the
One-Time-Programmable (OTP) memory. It means
that during startup, the content of the OTP memory is
copied to the registers. Once flashed the register
content cannot be modified anymore.
In order to set the content of a register, the user must
send a digital stream composed of the 4-bit REGISTER
WRITE command (0010), followed by a 4-bit register
address and the 8-bit value to be sent to the register.
The data stream, sent through the MOSI wire, is
therefore 16 bits long:
command reg. address MSB
value
LSB
0010
Once the command is sent, it will immediately be
effective and will affect the next data sent from the
MagAlpha.
Read back the register content
It might be helpful to check the content of a register,
for instance to verify that the programming was
successful. The user must send the REGISTER READ
command: 0001, then the 4-bit address of the register
under test. The last 8-bit of the stream will be ignored.
The user can send for instance 0000 0000:
command reg. address MSB
value
LSB
0001 xxxx 00000000
The MagAlpha response is within the same
transmission. In the first byte (simultaneous to the 4-bit
READ command and the 4-bit address), the MagAlpha
Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: [phone] | [e-mail] | www.sensimatech.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights
Reserved. MA700 Rev 1.0 September 2014
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