AS5045 datasheet(14/24 Pages) AMSCO

14 / 24 page

AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER

Revision 1.5

www.austriamicrosystems.com

Page 14 of 24

Programming the AS5045

After power-on, programming the AS5045 is enabled with

the rising edge of CSn and Prog = logic high. 16 bit

configuration data must be serially shifted into the OTP

by the zero position data (MSB first) and the Mode

setting bits. Data must be valid at the rising edge of CLK

(see Figure 10).

After writing the data into the OTP register it can be

permanently programmed by rising the Prog pin to the

programming voltage VPROG. 16 CLK pulses (tPROG) must

be applied to program the fuses (Figure 11). To exit the

programming mode, the chip must be reset by a power-

on-reset. The programmed data is available after the

next power-up.

Note: 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 should not exceed 50mm (2 inches). To suppress

eventual voltage spikes, a 10nF ceramic capacitor should

be connected close to pins VPROG and VSS. This

capacitor is only required for programming, it is not

required for normal operation. The clock timing tclk must

be selected at a proper rate to ensure that the signal

Prog is stable at the rising edge of CLK (see Figure 10).

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 section 3.8).

To compensate for the voltage drop across the VPROG

switching transistor, the applied programming voltage

may be set slightly higher (7.5 ~ 8.0V, see Figure 12).

OTP Register Contents:

CCW

Counter Clockwise Bit

ccw=0 – angular value increases in clockwise direction

ccw=1 – angular value increases in counterclockwise

direction

Z [11:0]:

Programmable Zero Position

PWM dis:

Disable PWM output

MagCompEn:

when set, activates LIN alarm both

when magnetic field is too high and

too low (see Table 5).

PWMhalfEn:

when set, PWM frequency is 122Hz or

2µs / step (when PWMhalfEN = 0,

PWM frequency is 244Hz, 1µs / step)

8.1

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 zero position.

For zero position programming, the magnet is turned to

the mechanical zero position (e.g. the “off”-position of a

rotary switch) and the actual angular value is read.

This value is written into the OTP register bits Z11:Z0

(see Figure 10) and programmed as described in

section 8.

Note: The zero position value may also be modified

before programming, e.g. to program an electrical zero

position that is 180° (half turn) from the mechanical zero

position, just add 2048 to the value read at the

mechanical zero position and program the new value into

the OTP register.

8.2

Repeated OTP Programming

Although a single AS5045 OTP register bit can be

programmed only once (from 0 to 1), it is possible to

program other, unprogrammed bits in subsequent

programming cycles. However, a bit that has already

been programmed should not be programmed twice.

Therefore it is recommended that bits that are already

programmed are set to “0” during a programming cycle.

8.3

Non-permanent Programming

It is also possible to re-configure the AS5045 in a non-

permanent way by overwriting the OTP register.

This procedure is essentially a “Write Data” sequence

(see Figure 10) without a subsequent OTP programming

cycle.

The “Write Data” sequence may be applied at any time

during normal operation. This configuration remains set

while the power supply voltage is above the power-on

reset level (see 3.6).

See Application Note AN5000-20 for further information.

AS5045 数据表(PDF) 14 Page - ams AG

AS5045 数据表(HTML) 14 Page - ams AG

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

数据表下载