A31316 datasheet(40/61 Pages) ALLEGRO

40 / 61 page

3D Magnetic Position Sensor IC

A31316

Allegro MicroSystems

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

access by either customer or factory, removing available support

options from the factory.

NOTE: When any of the EEPROM lock options are set, non-

destructive factory debug support is limited.

Table 28: Serial Communication Lockout Modes

mem_lock_sel[3:0] Lock Mode

Description

4’b0011

EELOCK

EEPROM Lock: Prevents writes to

EEPROM but all volatile registers including

shadow can be written. All registers and

EEPROM can be read normally.

4’b0110

WRLOCK

Write Lock: Prevents writing anything to

either EEPROM or registers. Factory debug

support is still available

4’b1100

FLOCK

Full Lock: Prevents writing and reading to

any register in the device.

EEPROM Margin Checking

The A31316 contains a test mode, EEPROM Margining, to check

the logic levels of the EEPROM bits. The EEPROM margining

is accessible with customer access. The EEPROM margining is

selectable to check all logic 1, logic 0, or both. The results of the

test are reported back in EEPROM registers.

Note: A fail of the margin test does not force the output to a

diagnostic state.

Error Flag Registers

The different error flags available in the A31316 are stored in the

primary memory space of register 0xA4. If the error conditions

are removed, all the non-critical error flags are cleared on a read

of this register, or after being sent out through the output proto-

cols. The register contents can be seen in Table 29.

Table 29: Error Registers

Address

NAME

Access

Bit

31…13

0xA3

error

OFE

SPE

EUE

OVD

UVD

ESE

POR

SRR

SLF

SAT

TSE

AOC

ACF

Analog Check Failure (ACF)

To ensure proper operation of the internal regulators, a voltage

check is done on the different reference sources for the analog and

digital circuitry, as well as for the Hall element drivers. If any of

these voltages deviate to where the accuracy of the part will be

in question, the ACF flag will be set and the device will go into a

state as defined in Table 32. If the voltages are detected to recover,

a read of the device register or reporting through the output modes

will clear the error flag so normal operation can resume. The ACF

flag can be disabled by setting acf_mask bit in EEPROM.

Angle Outside Clamp (AOC)

If the upper and lower clamps are set within the operating range

of the device, the AOC flag can be set as shown in Table 32 to

indicate the signal reaching this clamp value. If the signal moves

back within the range defined ang_clamp_high and ang_clamp_

low as described in the Output Clamps section, the AOC flag can

be removed by a read of the device register or through reporting

in the applicable output protocol. If the flag is not desired, the

EEPROM bit aoc_mask can be set. The AOC error is updated

with every angle update. However, the error may be suppressed

for up to 16 tupdate based on the fault_filt EEPROM setting.

Temperature Error (TSE)

The TSE flag is set if the temperature sensor output saturates

high, which indicates the ambient temperature is greater than

175.138°C or if the measured temperature is less than –54.963°C.

If any of these conditions occur the TSE flag will be set, and the

device will go into a state as defined in Table 32. If the tempera-

ture is detected to recover, a read of the device register or report-

ing through the output modes will clear the error flag so normal

operation can resume. The TSE flag can be disabled by setting

tse_mask bit in EEPROM. The TSE error is detected every nomi-

nal 1.5 ms and reaches the output after latest 1.62 ms.

Saturation Flag (SAT)

The Saturation Flag is provided to warn the user in case the mag-

netic signal is outside of the detectable range of the signal path. A

saturation can occur:

• In the ADC and filters, which would indicate a front-end gain

too large for the detected field, or

• A digital signal path saturation which would indicate a gain

setting too large.

If either of these conditions occur, the SAT flag will be set as

defined in Table 35. If the saturation condition is removed, the

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