ADIS16220

Preliminary Technical Data

Rev. PrE | Page 14 of 16

Table 26. GPIO_CTRL Bit Descriptions

Bit

Description (Default = 0x0000)

[15:10]

Not used

[9]

General-Purpose I/O Line 2 data level

[8]

General-Purpose I/O Line 1 data level

[7:2]

Not used

[1]

General-Purpose I/O Line 2, data direction control

1 = output, 0 = input

[0]

General-Purpose I/O Line 1, data direction control

1 = output, 0 = input

DIAGNOSTICS

In all of the error flags in DIAG_STAT, a 1 identifies an error

condition while a 0 signals normal operation. All of the flags

remain until the next capture or reset command (GLOB_CMD[4]

= 1). DIAG_STAT[1:0] return to 1 after the next sample (or

capture) if the error conditions still exist. DIAG_STAT[14:12]

provide flags to check the source of an event capture, prior to

reading the entire capture buffer. DIAG_STAT[10:8] offers flags

that check the peak values in the capture against the conditions

in the ALM_CTRL and ALM_MAGx registers. The flash test

produces an error flag in DIAG_STAT[6] to check if the sum of

the internal operating memory matches the sum of the same

flash memory locations. The capture period violation flag

(DIAG_STAT[4]) rises to 1 when the user attempts to use the

SPI while a capture sequence is in progress. Using the DIO1 line

in the factory default configuration as a busy indicator can help

prevent this violation. The SPI communication flag in

DIAG_STAT[3] raises to a Logic 1 when the total number of

SCLK clocks is not a multiple of 16 during a SPI transfer.

Table 27. DIAG_STAT Bit Descriptions

Bit

Description (Default = 0x0000)

[15]

Not used

[14]

AIN2 sample > ALM_MAG2

[13]

AIN1 sample > ALM_MAG1

[12]

Acceleration sample > ALM_MAGA

[11]

Error condition programmed into ALM_MAGS[11:0] and

ALM_CTRL[5:4] is true

[10]

Peak value in AIN2 data capture > ALM_MAG2

[9]

Peak value in AIN1 data capture > ALM_MAG1

[8]

Peak value in acceleration data capture > ALM_MAGA

[7]

Data ready, capture complete

[6]

Flash test, checksum flag

[5]

Self-test diagnostic error flag

[4]

Capture period violation/interruption

[3]

SPI communications failure

[2]

Flash update failure

[1]

Power supply above 3.625 V

[0]

Power supply below 3.15 V

Self-Test

The internal MEMS sensing element has an electrostatic self-

test function that simulates the physical displacement associated

with an acceleration event. There are two options for using this

feature to verify the integrity of the entire sensor signal chain. Set

GLOB_CMD[2] = 1 to execute an automatic self-test sequence,

which exercises the sensing element, observes the change in

output, records it into ST_DELTA, compares it with the acceptable

self-test response range in Table 1, and reports the pass/fail

result in DIAG_STAT[5].

Another option is to set MSC_CTRL[8] = 1 to manually

activate the sensing element. Then execute a manual capture,

which reflects the response associated with the self-test setting.

Table 28. MSC_CTRL Bit Descriptions

Bit

Description (Default = 0x0003)

[15:9]

Not used

[8]

Self-test enable, set to 1 to activate,

(returns to 0 when complete)

[7:2]

Not used

[1]

Power supply compensation, AIN1

1 = enable, 0 = disable

[0]

Power supply compensation, AIN2

1 = enable, 0 = disable

MSC_CTRL[1:0] provides an option for reducing the sensitivity

dependence on power supply for ratiometric sensors, such as

the ADXL001.

Table 29. ST_DELTA Bit Descriptions

Bit

Description

[15:0]

Acceleration data, twos complement, 19.073 mg/LSB

Table 30. FLASH_CNT Bit Descriptions

Bit

Description

[15:0]

Binary counter for writing to flash memory

SERIALIZATION

LOT_ID1 and LOT_ID2 combine to provide a unique lot code

that is 24 bits in length. SERIAL_NUM provides a unique serial

number for each device within a given lot.

Table 31. LOT_ID1 Bit Descriptions

Bit

Description

[15:8]

Lot identification code, least significant byte

[7:0]

Reserved for internal use, do not use

Table 32. LOT_ID2 Bit Descriptions

Bit

Description

[15:0]

Lot identification code, most significant bytes

Table 33. SERIAL_NUM Bit Descriptions

Bit

Description

[15:0]

Serial number, lot-specific