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AS7331

Functional Description

Datasheet

• PUBLIC

DS001047

• v4-00 • 2023-Mar-24

│ 29

The following example of a SYNS mode shows the correct measurement procedure but with an

unfavorable chosen application. After the start of measurement with bit OSR:SS =

“1” only the falling

edges marked in red (see Figure 25) at pin SYN are accepted as the start condition. Because of the

tight distances of the SYN edges, many falling edges are ignored during the startup phase (TSTARTPD),

conversion time (TCONV), and pause time (TBREAK).

Figure 25:

Principle Sequence of Measurement in SYNS Mode (OSR:PD

, OSR:SS are set to “1”)

Continuously occurring SYN pulses (e.g. generated by a PWM controlling the measurement mode

SYND) are ignored in the configuration state and whilst pause time, TBREAK, (see Figure 26) is

activated. It is recommended to increase the default value of the BREAK register accordingly, if the

time reference result OUTCONV must be read via the I²C interface. The EDGES register gives the

conversion time, but as shown in Figure 26 the real conversion time is always represented by TCONV at

pin READY. Furthermore, the output result OUTCONV can be used to get the right measurement

result (see also chapters 7.4 and 7.6). Figure 26 shows the principle sequence of measurement in

SYND mode, which is ready for wake-up after switching off the power down

state with OSR:PD = “0”,

and setting OSR:SS to

“1” in the configuration state, then waiting for the start via pin SYN (with

exemplary settings of EDGES = 06h and CREG3:SB =

“1” for energy-saving during pause time

TBREAK).

READY

SYN

MRES1 …

MRES3

start

RESULTS 1

POWDOWN

STATE

MEAS

PAUSE

POWDOWN

MEASUREMENT 1

TBREAK

I²C activity

OSR

C0h

data

fetch

TCONV

TSTARTPD

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