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AS73211

Functional Description

Datasheet

• PUBLIC

DS000556

• v3-01 • 2018-Feb-07

│ 22

In case of the Device Operational State (DOS) is set to Measurement mode the start/stop of a

measurement is possible by setting the OSR:SS bit and reading of measurement data. The Power

Down can be switched on and off by the bit OSR:PD (Figure 1). Switching on Power Down via bit

OSR:PD = ‚1‘ the AS73211 changes to the Power Down state after the end of an ongoing

measurement. Switching off Power Down (OSR:PD = ‚0‘) results in a change to the Idle state (IDLE for

waiting) or Standby state depending on bit CREG3:SB. This change to another operational state is

delayed by the startup time TSTARTPD of typically 1.2ms. A conversion can start in all measurement

modes

while the Power Down state is activated (OSR:PD = ‚1‘). In the measurement modes CMD and

CONT it is done by se

tting the bit OSR:SS to ‚1‘. In addition, the falling edge of the signal at pin SYN

for the measurement modes SYNS and SYND initiate the start. In all cases, the start of conversion is

delayed by the startup time TSTARTPD. After the conversion in the CMD, SYNS and SYND modes

the AS73211 changes back into the Power Down state, whereas the measurement of the CONT mode

is interactive until it is stopped by setting bit OSR:SS = to ,0‘ before it changes back into the Power

Down state.

There are two methods for startup the AS73211:

After applying the power supply voltage including power-on reset or after software reset the bit

OSR:PD must be set to ‚0‘ via I²C interface communication. The analog part and the internal

clock system starts to work along the defined configuration of the AS73211. Nevertheless, it is

still possible to change the configuration in front of time b) of Figure 20. The Device Operational

State changes to Measurement state to start the measurement (OSR:SS = ‚1‘) without further

delay caused by energy saving options.

Figure 20 shows the principle sequence after power-on reset and separated writing of the bits

OSR:PD, OSR:DOS and OSR:SS:

OSR programming: 02h, after TSTARTPD continuing within Configuration state only,

OSR programming: 03h, change to Measurement state

– waiting is shown as IDLE.

Figure 20:

Principle Sequence After Power-On Reset and Separated Writing of the Bits OSR:PD, OSR:DOS

and OSR:SS

POWDOWN

MEASUREMENT

CONFIGURATION

IDLE

STATE

TSTARTPD

I²C activity

Start

OSR:SS ← ‚1'

OSR:DOS

011b

OSR:PD ← ‚0'

AS73211 数据表(PDF) 23 Page - OSRAM GmbH

AS73211 数据表(HTML) 23 Page - OSRAM GmbH

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