Data Sheet

ams Datasheet Page 13
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CCS811 − Application Information
I²C Interface
I²C transactions require a register address to be selected
(written) and followed by data, as described by the transaction
types in the subsections below. Each Register location
corresponds to a byte or multiple bytes.
Multiple reads or writes in a single sequence will be to or from
the same location (the address does not increment).
Therefore, registers are sometimes referred to as mailboxes in
this document.
I²C Register Write
Figure 9:
I²C Register Write
As shown above, a transaction may be:
• Single Byte to select a register address for subsequent
read
• Two Bytes to select a register address and write a byte to
it, typically to set a single-byte register value
• Multi-Bytes to select a register address and write several
bytes to it, typically to set multiple configuration bytes
SL AVE ADD RES SS W A DATA(REG ADDR)
DATA
A P
SL AVE ADD RES SS W A DATA(REG ADDR) A
PSL AVE ADD RES SS W A DATA(REG ADDR) A
P
A
A
ADATA
DATA
Write, register address only
Write value to register
Write multiple data
values to register
(mailbox)
From master to slave
From slave to master
S
Start condition
P
STOP condition
W
R
Write
Read
A
Acknowledge