Datasheet

Timing in SpO
2
Mode
The internal FIFO stores up to 32 samples, so that the
system processor does not need to read the data after
every sample. SpO
2
can be calibrated using temperature
data. In this case, the temperature does not need to be
sampled very often – once a second or every few seconds
should be sufficient.
Figure 4. Timing for Data Acquisition and Communication When in SpO
2
Mode
Table 15. Events Sequence for Figure 4 in SpO
2
Mode
EVENT DESCRIPTION COMMENTS
1
Enter into SpO
2
Mode. Initiate a
Temperature measurement.
I
2
C Write Command sets MODE[2:0] = 0x03 and set A_FULL_EN.
Then, to enable and initiate a single temperature measurement, set
TEMP_EN and DIE_TEMP_RDY_EN.
2
Temperature Measurement Complete,
Interrupt Generated
DIE_TEMP_RDY interrupt triggers, alerting the central processor to read
the data.
3 Temp Data is Read, Interrupt Cleared
4 FIFO is Almost Full, Interrupt Generated Interrupt is generated when the FIFO almost full threshold is reached.
5 FIFO Data is Read, Interrupt Cleared
6 Next Sample is Stored
New Sample is stored at the new read pointer location. E󰀨ectively, it is
now the rst sample in the FIFO.
INT
I
2
C BUS
LED
OUTPUTS
~
~
~
SAMPLE #1 SAMPLE #2 SAMPLE #3 SAMPLE #16 SAMPLE #17
1 4 5 6
TEMP
SENSOR
TEMPERATURE SAMPLE
2 3
29ms
15ms TO 300
ms
IRRED IRRED IRRED IRRED IRRED IRRED IRRED
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MAX30101 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health