AS5035 −
Zero Position Programming
Zero Position Programming
Zero Position Programming is an OTP option that simplifies assembly of a system, as the magnet does not need to be manually adjusted to the mechanical zero position. Once the assembly is completed, the mechanical and electrical zero positions can be matched by software. Any position within a full turn can be defined as the permanent new index position.
For Zero Position Programming, the magnet is turned to the mechanical zero position (e.g. the “OFF”-position of a rotary switch) and an automatic zero position programming is applied.
The zero position is programmed to an accuracy of ±0.35°.
Figure 18:
Hardware Connection of AS5035 to AS50xx Demoboard for Zero Position Programming
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ams Datasheet (discontinued)
[v2-02] 2017-Jun-23
AS5035 −
Zero Position Programming
OTP Programming Timing
OTP programming requires access to the factory settings register of the AS5035. Improper or accidental modification of the factory settings may render the chip unusable. Therefore the Zero Position and CCW programming is recommended only with
ams
proprietary hardware and software.
Note(s):
During the programming process, the transitions in the programming current may cause high voltage spikes generated by the inductance of the connection cable. To avoid these spikes and possible damage to the IC, the connection wires, especially the signals Prog and VSS must be kept as short as possible. The maximum wire length between the VPROG switching transistor and pin Prog (see
Figure 18
) should not exceed 50mm (2 inches). To suppress eventual voltage spikes, a 10nF ceramic capacitor should be connected close to pins
Prog and VSS. This capacitor is only required for programming, it is not required for normal operation.
The clock timing t clk
must be selected at a proper rate to ensure that the signal Prog is stable at the rising edge of CLK (see
Figure 19 ). Additionally, the programming supply voltage
should be buffered with a 10μF capacitor mounted close to the switching transistor. This capacitor aids in providing peak currents during programming.
The specified programming voltage at pin Prog is 7.3 – 7.5V (see
Programming Conditions
). To compensate for the voltage drop across the VPROG switching transistor, the applied programming voltage may be set slightly higher (7.5 -8.0V).
CCW Bit Programming
The absolute angular output value, by default, increases with clockwise rotation of the magnet (top view). Setting the
CCW-bit (see
Figure 19 ) allows for reversing the indicated
direction, e.g. when the magnet is placed underneath the IC:
CCW = 0 – angular value increases clockwise;
CCW = 1 – angular value increases counterclockwise.
Note(s):
Further information on the required hardware and software for Zero Position programming of the AS5035 can be found in the “AS5035” section of the
ams
website: www.ams.com/AS5035
ams Datasheet (discontinued)
[v2-02] 2017-Jun-23
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Figure 19:
Programming Access – Write Data
AS5035 −
Zero Position Programming
Figure 20:
Complete Programming Sequence
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ams Datasheet (discontinued)
[v2-02] 2017-Jun-23
