User Manual

Page 22 ams Datasheet
Document Feedback [v1-06] 2019-Feb-07
CCS811 − Application Register Overview
THRESHOLDS Register (0x10)
If ‘interrupt on threshold change’ has been set in the Mode
register (see above), the values in this multi- byte write only
register are used to determine the thresholds.
Figure 21:
Thresholds Register Byte Order
An interrupt is asserted if the eCO
2
value moved from the
current range (Low, Medium, or High) into another range by
more than 50ppm.
• Low to Medium Threshold default = 1500ppm = 0x05DC
• Medium to High Threshold default = 2500ppm = 0x09C4
BASELINE Register (0x11)
A two byte read/write register which contains an encoded
version of the current baseline used in Algorithm Calculations.
A previously stored value may be written back to this two byte
register and the Algorithms will use the new value in its
calculations (until it adjusts it as part of its internal Automatic
Baseline Correction). For more information, refer to ams
application note AN000370: CCS811 Clean Air Baseline Save and
Restore.
HW_ID (Hardware identifier) Register (0x20)
Single byte read only register which holds the HW ID which is
0x81 for this family of CCS81x devices.
HW_Version (Hardware Version) Register
(0x21)
Single byte read only register which holds the Hardware Major
and Minor Hardware versions.
The top four bits read major hardware version 1 – identifying
the product as CCS811. The bottom four bits identify any build
variant. The default value is 0x1X.
Byte 0 Byte 1 Byte 2 Byte 3
Low to Medium Threshold Medium to High Threshold
High Byte Low Byte High Byte Low Byte