AD7616BSTZ datasheet(36/51 Pages) AD

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Data Sheet

AD7616

Rev. 0 | Page 35 of 50

SEQUENCER

The AD7616 features a highly configurable on-chip sequencer.

The functionality and configuration of the sequencer is

dependent on the mode of operation of the AD7616.

In hardware mode, the sequencer is sequential only. The

sequencer always starts converting at Channel V0A and

Channel V0B and converts each subsequent channel up to the

configured end channel.

In software mode, the sequencer has additional functionality

and configurability. The sequencer stack has 32 uniquely

configurable sequence steps, allowing any channel order to be

programmed. Additionally, any Channel VxA input can be

paired with any Channel VxB input or diagnostic channel.

The sequencer can be operated with or without the burst

function enabled. With the burst function enabled, only one

CONVST pulse is required to convert every channel in a

sequence. With burst mode disabled, one CONVST pulse is

required for every conversion step in the sequence. See the

Burst Sequencer section for additional details on operating in

burst mode.

HARDWARE MODE SEQUENCER

In hardware mode, the sequencer is controlled by the SEQEN pin

and the CHSELx pins. The sequencer is enabled or disabled

when the AD7616 is released from full reset. The logic level of

the SEQEN pin when the RESET pin is released determines

whether the sequencer is enabled or disabled (see Table 17 for

settings). After the RESET pin is released, the function is fixed

and a full reset via the RESET pin is required to exit the

function and set up an alternative configuration.

Table 17. Hardware Mode Sequencer Configuration

SEQEN

Interface Mode

Sequencer disabled

Sequencer enabled

When the sequencer is enabled, the logic levels of the CHSELx pins

determine the channels selected for conversion in the sequence.

The CHSELx pins at the time RESET is released determine the

initial settings for the channels to convert in the sequence. To

reconfigure the channels selected for conversion thereafter, set

the CHSELx pins to the required setting for the duration of the

final BUSY pulse before the current conversion sequence is

complete. See Figure 61 for further details.

Table 18. CHSELx Pin Decoding Sequencer

Channel Selection Input Pin

Analog Input Channels for

Sequential Conversion

CHSEL0

CHSEL1

CHSEL2

V0x only

V0x to V1x

V0x to V2x

V0x to V3x

V0x to V4x

V0x to V5x

V0x to V6x

V0x to V7x

SOFTWARE MODE SEQUENCER

In software mode, the AD7616 contains a 32-layer fully

configurable sequencer stack. Control of the sequencer is

achieved by programming the configuration register and

sequencer stack registers via the parallel or serial interface.

Each stack step can be individually programmed to pair any

input from Channel VxA to any input from Channel VxB, or

any diagnostic channel can be selected for conversion. The

sequencer depth can be set to any length from 1 to 32 layers.

The sequencer depth is controlled via the SSRENx bit. Set the

SSRENx bit in the sequencer stack register corresponding to the

last step required. The channels to convert are selected by

programming the ASELx and BSELx bits in each sequence stack

The sequencer is activated by setting the SEQEN bit in the

configuration register to 1.

Figure 61. Hardware Mode Sequencer Configuration

RESET

SEQEN

CONVST

BUSY

CHx

CHy

CHz

CHSEL2 TO CHSEL0

A/B0

A/Bx

A/B0

A/By

A/B0

DATA

INITIAL SETUP

CONFIGURE POINT

A/Bx-1

A/By-1

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