User manual

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C control interface VL6180X
38/79 DocID026171 Rev 6
As data is received by the slave it is written bit by bit to a serial/parallel register. After each
data byte has been received by the slave, an acknowledge is generated, the data is then
stored in the internal register addressed by the current index.
During a read message, the contents of the register addressed by the current index is read
out in the byte following the device address byte. The contents of this register are parallel
loaded into the serial/parallel register and clocked out of the device by the falling edge of
SCL.
Figure 24. Single location, single read
At the end of each byte, in both read and write message sequences, an acknowledge is
issued by the receiving device (that is, the sensor for a write and the master for a read).
A message can only be terminated by the bus master, either by issuing a stop condition or
by a negative acknowledge (that is, not pulling the SDA line low) after reading a complete
byte during a read operation.
The interface also supports auto-increment indexing. After the first data byte has been
transferred, the index is automatically incremented by 1. The master can therefore send
data bytes continuously to the slave until the slave fails to provide an acknowledge or the
master terminates the write communication with a stop condition. If the auto-increment
feature is used the master does not have to send address indexes to accompany the data
bytes.
Figure 25. Multiple location write
S As
ADDRESS[7:0]
As
INDEX[15:8]
INDEX[7:0]
As P
0x52 (write)
S As
ADDRESS[7:0]
Am
DATA[7:0]
P
0x53 (read)
S As
ADDRESS[7:0]
As
INDEX[15:8]
INDEX[7:0]
As
0x52 (write)
PAs
DATA[7:0]
As
DATA[7:0]
As
DATA[7:0]