ADIS16228SLASHPCBZ datasheet(24/28 Pages) AD

24 / 28 page

ADIS16228

Data Sheet

Rev. B | Page 24 of 28

OPERATION MANAGMENT

The ADIS16228 SPI port supports two different communica-

tion commands while it is processing data or executing a command

associated with the GLOB_CMD register (see Table 64): reading

DIAG_STAT (DIN = 0x3C00) (see Table 65) and the escape code

(DIN = 0xE8E8). The SPI ignores all other commands when the

processor is busy.

Software Busy Indicator

Use the DIAG_STAT read command to poll DIAG_STAT[7],

which is equal to 0 when the processor is busy and equal to 1

when the processor is idle and data is ready for SPI commu-

nications.

Software Escape Code

The only SPI command that is available when the processor is

busy capturing data is the escape code, which is 0xE8E8. This

command is not available for interrupting any other processing

tasks. Send this command in a repeating pattern, with a small delay

between each write cycle, to the DIN pin while monitoring

DIAG_STAT[7]. The following code example illustrates this

process:

DIAG_STAT = 0;

DIAG_STAT = read_reg(0x3C);

while ((DIAG_STAT & 0x0080) == 0)

{

write_reg(0xE8E8)

delay_us(50)

DIAG_STAT = read_reg(0x3C)

}

INPUT/OUTPUT FUNCTIONS

The DIO_CTRL register (see Table 66) provides configuration

control options for the two digital I/O lines, DIO1 and DIO2.

Busy Indicator

The busy indicator is an output signal that indicates internal

processor activity. This signal is active during data recording events

or internal processing (GLOB_CMD functions, for example). The

factory default setting for DIO_CTRL sets DIO1 as a positive,

active high, busy indicator signal. When configured in this manner,

use this signal to alert the master processor to read data from

data buffers.

Trigger Input

The trigger function provides an input pin for starting record

events with a signal pulse. Set DIO_CTRL[7:0] = 0x2F (DIN =

0xB62F) to configure DIO2 as a positive trigger input and keep

DIO1 as a busy indicator. To start a trigger, the trigger input signal

must transition from low to high and then from high to low. The

recording process starts on the high-to-low transition, as shown

in Figure 22, and the pulse duration must be at least 2.6 μs.

DIO1

DIO2

CAPTURE TIME

∆t

∆t ≥ 2.6µs

Figure 22. Manual Trigger/Busy Indicator Sequence Example

Alarm Indicator

DIO_CTRL[5:2] provide controls for establishing DIO1 and/or

DIO2 as a general alarm output indicator that goes active when

any of the flags in DIAG_STAT[13:8] is active. For example, set

DIO_CTRL[7:0] = 0x12 (DIN = 0xB612) to configure DIO2 as

a generic alarm indicator with an active high polarity. ALM_

CTRL[6] (see Table 26) provides an additional control, which

enables DIO2 to reflect Alarm 2 and DIO1 to reflect Alarm 1 when

they are selected as alarm indicators in DIO_CTRL[5:2]. For

example, set DIO_CTRL[7:0] = 0x17 (DIN = 0xB617) and set

ALM_CTRL[6] = 1 (DIN = 0xB440) to establish DIO2 as an active

high Alarm 2 indicator and DIO1 as an active high Alarm 1

indicator. Set GLOB_CMD[4] = 1 (DIN = 0xBE10) to clear the

DIAG_STAT error flags and restore the alarm indicator signal

to its inactive state.

Table 66. DIO_CTRL (Base Address = 0x36), Read/Write

Bits

Description (Default = 0x000F)

[15:6]

Not used

[5:4]

DIO2 function selection

00 = general-purpose I/O (use GPIO_CTRL)

01 = alarm indicator output (per ALM_CTRL)

10 = trigger input

11 = busy/data-ready indicator output

[3:2]

DIO1 function selection

00 = general-purpose I/O (use GPIO_CTRL)

01 = alarm indicator output (per ALM_CTRL)

10 = trigger input

11 = busy/data-ready indicator output

DIO2 line polarity

1 = active high

0 = active low

DIO1 line polarity

1 = active high

0 = active low

General-Purpose I/O

If the DIO_CTRL register configures either DIO1 or DIO2 as

a general-purpose digital line, use the GPIO_CTRL register (see

Table 67) to configure its input/output direction, set the output

level when configured as an output, and monitor the status of

an input.

Table 67. GPIO_CTRL (Base Address = 0x38), Read/Write

Bits

Description (Default = 0x0000)

[15:10]

Not used

DIO2 output level

1 = high; 0 = low

DIO1 output level

1 = high; 0 = low

[7:2]

Reserved

DIO2 direction control

1 = output; 0 = input

DIO1 direction control

1 = output; 0 = input

ADIS16228/PCBZ 数据表(PDF) 24 Page - Analog Devices

ADIS16228/PCBZ 数据表(HTML) 24 Page - Analog Devices

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 25 26 27 28

数据表下载