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ams Datasheet Page 9
[v1-06] 2019-Feb-07 Document Feedback
CCS811 − Detailed Description
State Machine
The state machine for CCS811 is shown below:
Figure 9:
CCS811 State Machine
When powering on the CCS811, a typical action is to transition
from Boot to App mode, a write to register APP_START with no
data is required. Before performing the write the STATUS
register should be accessed to check if there is an application
present. When in App mode, the next step is to start measuring.
For example, writing 1 to register MEAS_MODE selects
operation mode Mode1s: every second new measurement data
(CO
2
, TVOC) becomes available.
A write to register SW_RESET (with a four byte “cookie”) will
restart the CCS811 in Boot mode. The key feature of the Boot
mode is replacement of the application firmware. First erase the
application firmware (write to APP_ERASE), next write the new
firmware image (use multiple 8 byte writes via APP_DATA), and
finally verify the written firmware (with a write to APP_VERIFY).
For details on these registers, see later sections in this
datasheet.
Detailed Description