Maxim Integrated
Page 13 of 24
2.2.2 Pure Raw Data Collection
The host can configure the MAX32664C to work in Raw-Only mode (no algorithm).
the set of commands that are needed to work in this mode. In this case, only LED counters and
accelerometer data will be included in the received samples.
Table 6. Host Commands—WSpO
2
Pure Raw Data
#
HOST COMMAND
(HEX)
COMMAND DESCRIPTION
RESPONSE
(HEX)
ST
A
R
T
A
LG
O
R
IT
H
M
Host initializes MAX32664C in pure raw data using following commands:
1.1
AA 10 00 01
Set output mode to sensor only.
AB 00
1.2
AA 10 01 05
Set sensor hub interrupt threshold.
AB 00
1.3
AA 44 00* 01 00
Enable AFE (e.g., MAX86141)* with sensor hub
samples.
AB 00
1.4
AA 44 04* 01 00 (if sensor
hub accelerometer is used)
AA 44 04* 01 01 (if host
accelerometer is used)
Enable accelerometer with sensor hub or host-side
accelerometer.*
AB 00
1.5
AA 40 00 12 18
Set sample rate of MAX86141 to 100Hz with 1
sample averaging.
AB 00
1.6
AA 40 00 11 3F
Set MAX86141 to integration time: 117
μ
s and ADC
1/2 range: 32
μ
A.
AB 00
1.7
AA 40 00 23 00
Set MAX86141 LED1 (green) current to 0.
AB 00
1.8
AA 40 00 24 [7F]
Set MAX86141 LED2 (IR) current to half of full scale.
Reduce [7F] if signal is saturated.
AB 00
1.9
AA 40 00 25 [7F]
Set MAX86141 LED3 (red) current to half of full
scale. Reduce [7F] if signal is saturated.
AB 00
1.10 AA 40 00 2A 3C
Set MAX86141 LEDs 2 and 3 current full range =
124mA.
AB 00
1.11 AA 40 00 20 23
Set MAX86141 LED sequence.
LED3 (red) -> LED2 (IR)
AB 00
1.12 AA 40 00 09 7C
Set MAX86141 FIFO interrupt threshold to 124.
AB 00
1.13 AA 40 00 0A 0E
Set MAX86141 FIFO configuration.
AB 00
1.14 AA 40 00 02 86
Set MAX86141 Interrupt configuration.
AB 00
R
EA
D
IN
G
S
A
M
PL
ES
Host reads samples upon receiving MFIO interrupt by MAX32664C (repeated as needed):
2.1
AA 00 00
Read sensor hub status byte:
Bit 0: Sensor comm error
Bits 1 and 2: Reserved
Bit 3: FIFO filled to threshold (DataRdyInt)
Bit 4: Output FIFO overflow (FifoOutOvrInt)
Bit 5: Input FIFO overflow (FifoInOverInt)
Bit 6: Sensor hub busy (DevBusy)
Bit 7: Reserved
If DataRdyInt is set, proceed to next step.
AB 00 08
2.2
AA 12 00
Get the number of samples (nn) in the FIFO.
AB 00 nn
2.3
AA 12 01
Read the data stored in the FIFO; nn samples (24
bytes each) will be included. The format of samples
is shown in
AB 00
data_for_
nn_samples
ST
O
P
Host ends the procedure:
3.1
AA 44 00* 00
Disable AFE (e.g., MAX86141).*
AB 00
3.2
AA 44 04* 00
Disable accelerometer.*
AB 00
**Provided indexes are examples for sensors such as the MAX86141 AFE or KX122
accelerometer.
