Datasheet

Timing in HR Mode

The internal FIFO stores up to 32 samples, so that the

system processor does not need to read the data after

every sample. In HR mode (Figure 5), unlike in SpO

mode, temperature information is not necessary to interpret

the data. The user can select either the Red, IR, or Green

LED channel for heart rate.

Figure 5. Timing for Data Acquisition and Communication When in HR Mode

Table 16. Events Sequence for Figure 5 in HR Mode

EVENT DESCRIPTION COMMENTS

1 Enter into Mode

C Write Command sets MODE[2:0] = 0x02. Mask the A_FULL_EN

Interrupt.

2 FIFO is Almost Full, Interrupt Generated Interrupt is generated when the FIFO has only one empty space left.

3 FIFO Data is Read, Interrupt Cleared

4 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

C Bus

LED

OUTPUTS

SAMPLE #1 SAMPLE #2 SAMPLE #3 SAMPLE #30 SAMPLE #31

1 2 3 4

15ms TO 300ms

IR IR IR IR IR IR

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Maxim Integrated

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MAX30101 High-Sensitivity Pulse Oximeter and

Heart-Rate Sensor for Wearable Health