FAQs AS50/51/52xx

Yes, you can overwrite the OTP registers, even after they are programmed in both 3.3V and 5V- mode without any additional programming voltage. The overwritten information is certainly temporary; it will be lost with power down. The chip will always boot with the “hard programmed” settings in the OTP. “Soft writing” is possible by reading and writing the complete OTP registers, including the factory settings, but without subsequent programming.
Accidental or deliberate modification of the factory settings may render the chip unusable. However one could use the AS5040 demoboard, which also allows overwriting the OTP settings, like incremental mode, zero position, direction of rotation etc..
If the factory settings are accidentally modified but not yet programmed, the chip can always be reset to the hard programmed settings of the OTP-register by a power-on-reset.

You can also temporarily overwrite the user OTP settings without reading and re-writing the factory settings, but only once per power-up session. This can be done by terminating the OTP programming sequence (as shown in the datasheet) with a CSN= low after the 16th clock.

See Application Note AN5040-20 for more details.

Yes, see Q63:Can the AS5035/40/43/45 be "soft" programmed with 3.3V?

The Daisy-chain mode is only for reading angular data, not for OTP writing. In order to program devices connected in daisy-chain, each device must be programmed individually by shifting data into the PROG input of each device in the chain separately. Since the PROG input is connected to an output (DO), a diode must be inserted (Anode at DO, Cathode at PROG) to avoid overvoltage at the DO output during programming.

Yes !. Just use the demoboard software of the same type as the external encoder, independent what demoboard you use. See application note AN5000-10 :Hardware /Software compatibility Overview.

Connect the external sensor to the demoboard as shown:

To program AS5000-series encoders, you have several options.

a) use the corresponding demoboard & software.
You can program an AS5040 with an AS5040 demoboard, an AS5045 with an AS5045 demoboard, and so on.
AS5035 does not have its own demoboard, it can be programmed with an AS5040 / -43 or -45 demoboard.

b) use the AS50xx programmer & software
The programmer is similar in hardware to the demoboard, but comes in a sealed plastic housing and has additional features, like an ADC to use the analog readback option for qualitative verification of the OTP programming.
It is a “one tool fits all” device that can be used to program any AS5000-series encoder. This tool and the graphical user interface (GUI) are available on request from austriamicrosystems.

c) use any demoboard to program any encoder
You can program any AS5035/40/43/45 on any demoboard, using the software of the device to be programmed.
see also: Q66:Can I connect any AS504x-based encoder to any demoboard?

d) use a demoboard or programmer hardware & SDK
With a proper demoboard or programmer hardware, the user can write his own software to read and program an encoder IC connected to the hardware. The software development kit (SDK) is available for free download from the austriamicrosystems website and allows rapid program generation using simple and easy to use commands.

This behaviour is intentionally controlled by the Demoboard, it is not a malfunction of the IC!
Reason: The PWM frequency is trimmed by factory test to 976Hz +/-5% on the AS5040.
And to 244Hz +/-5% (optional 122Hz +/-5%) on the AS5045 (see datasheets).

The trimming information is stored in the OTP factory settings.

When the user wants to modify the OTP (e.g. Zero Position Programming, Incremental mode setting, etc.) the demoboard software temporarily resets the factory setting register to "0000" as a safety measure to avoid any double or wrong programming of the factory settings by the user.

Clearing the factory OTP register also clears the PWM frequency trimming temporarily.

The factory OTP register and thus the PWM frequency is set correctly again with the next power up cycle. In normal operation, this phenomenon cannot occur, as the user has no access to the OTP register. It can only occur during 32-bit OTP programming, where the user is advised to set all non-modified OTP bits to "0".