Configuration¶

Every setting of the AS5047U, the call that changes it, its register and reset value, and two complete setups.

All settings live in the non-volatile register block (0x0015 to 0x001B). Writes go to the volatile copy and are lost at power-off unless you burn them (OTP programming). A chip that was never programmed starts with every register at 0x0000, which gives the defaults below. Every snippet here is compiled from tests/docs/configuration.cpp.

Compile-time defaults¶

Define these for the whole build (for example target_compile_definitions(my_app PRIVATE CONFIG_AS5047U_FRAME_24), or in your sdkconfig.h); inc/as5047u_config.hpp reads them.

Define	Effect	Without it
`CONFIG_AS5047U_FRAME_24`	The constructor's default format is `SPI_24`	`SPI_16`
`CONFIG_AS5047U_FRAME_32`	The constructor's default format is `SPI_32`	`SPI_16`
`CONFIG_AS5047U_CRC_RETRIES=n`	Default `retries` argument of every call	`0`

The repository has no Kconfig file of its own; an ESP-IDF project that wants a menu entry defines these symbols in its own Kconfig.projbuild.

Settings¶

Setting (field)	Call	Reset value
Zero position (`ZPOSM`, `ZPOSL`)	`SetZeroPosition()`	0
Direction (`SETTINGS2.DIR`)	`SetDirection()`	Clockwise counts up
DAEC (`SETTINGS2.DAECDIS`)	`SetDynamicAngleCompensation()`	On
What 0x3FFF returns (`SETTINGS2.Data_select`)	`SetAngleOutputSource()`	ANGLECOM
Adaptive filter (`DISABLE.FILTER_disable`)	`SetAdaptiveFilter()`	On
Filter coefficients (`SETTINGS1.K_min`, `K_max`)	`SetFilterPreset()`	K = 2 to 6
150 °C in 3.3 V mode (`SETTINGS2.NOISESET`)	`Set150CTemperatureMode()`	Off: up to 125 °C
ABI, UVW, PWM (`DISABLE`, `SETTINGS2`)	`ConfigureInterface()`	PWM off
ABI resolution (`SETTINGS3.ABIRES`)	`SetABIResolution()`	1024 pulses
Index pulse width (`SETTINGS2.IWIDTH`)	`SetIndexPulseLength()`	3 LSB
UVW pole pairs (`SETTINGS3.UVWPP`)	`SetUVWPolePairs()`	1
ABI hysteresis (`SETTINGS3.HYS`)	`SetHysteresis()`	1 LSB (0.17°)

DAEC is the dynamic angle error compensation; SetFilterParameters() sets the filter codes directly. ABI and UVW are on after reset. Directions are seen from the top of the chip. The ABI decimal mode (SETTINGS2.ABI_DEC) has no setter; see below.

Filter presets¶

The adaptive filter picks a coefficient K between K_min and K_max depending on acceleration. Low K is less noise and more latency.

`FilterPreset`	K_min, K_max	Velocity noise (Figure 17)	Corner frequency
`LowNoise`	0, 0	5.8 °/s rms	48 Hz
`Balanced`	2, 3	8.4 to 19.8 °/s rms	194 to 387 Hz
`HighBandwidth`	6, 6	244.9 °/s rms	3095 Hz

SetFilterParameters() takes the 3-bit register codes, not K: the mapping is not linear (Figure 13: K_min code 000 is K = 2, 101 is K = 0; K_max code 000 is K = 6, 110 is K = 0). The presets write the right codes.

ABI resolution¶

`SetABIResolution()`	Steps per turn	Pulses per turn	ABIRES
14	16384	4096	`100`
13	8192	2048	`011`
12 (default)	4096	1024	`000`
11	2048	512	`001`
10	1024	256	`010`

With ABI_DEC = 1 the same codes give decimal counts from 1000 down to 25 pulses per turn; set it with WriteReg() (API guide).

Interface combinations¶

ConfigureInterface(abi, uvw, pwm):

`abi`	`uvw`	`pwm`	Outputs
true	false	false	A, B, I
true	false	true	A, B, I; PWM on W
false	true	false	U, V, W
false	true	true	U, V, W; PWM on I
true	true	any	A, B, I and U, V, W; `UVW_ABI` = 0, so PWM (if set) takes the W pin
false	false	true	PWM on W
false	false	false	ABI and UVW tristated

Setups¶

Motor commutation and speed control¶

// BLDC commutation and speed: fast response, UVW to the gate driver, ABI to the MCU.
bool ok = true;
ok = ok && encoder.SetDynamicAngleCompensation(true);       // latency compensated
ok = ok && encoder.SetFilterPreset(FilterPreset::HighBandwidth);  // K = 6
ok = ok && encoder.ConfigureInterface(true, true, false);   // ABI and UVW, no PWM
ok = ok && encoder.SetUVWPolePairs(7);
ok = ok && encoder.SetABIResolution(14);                    // 4096 pulses per turn
return ok;

Slow or static positioning¶

// Static or slow positioning (under about 100 rpm): lowest noise.
using Hys = AS5047U_REG::SETTINGS3::Hysteresis;
bool ok = true;
ok = ok && encoder.SetDynamicAngleCompensation(false);      // 0.016 deg rms less
ok = ok && encoder.SetFilterPreset(FilterPreset::LowNoise); // K = 0
ok = ok && encoder.SetHysteresis(Hys::LSB_2);
ok = ok && encoder.ConfigureInterface(false, false, false); // SPI only, rest off
return ok;

The datasheet recommends turning DAEC off under about 100 rpm: it removes 0.016° rms of noise and the latency it compensates does not matter at low speed.

Next: OTP programming to make a setup permanent.