MLX75030 Datasheet, PDF (62/72 Pages) Melexis Microelectronic Systems – Universal ActiveLight Sensor Interface

MLX75030 Universal ActiveLight Sensor Interface
Datasheet
7.9. Global Timing Diagrams
A global timing diagram with separate SM-RO cycles is given in Figure 19. After power-up there is a Power-On-Reset phase
(POR) to initialize the sensor into a reset state. When the device is ready to accept the first command, the DR pin goes high.
In Figure 19 the first command is the WR command to define the contents of the user registers (optionally). The first
measurement cycle is e.g. initiated by uploading a SM command. After completion of the measurement cycle, the DR goes
high. This indicates that the read-out cycle can be started. A RO command has to be uploaded to bring the data on the MISO
pin. When the read-out is completed, a new measurement cycle can be started. In Figure 19 a SM command is used. This
starts a next measurement cycle. Once DR is high, a read-out can be done again.
In between different Measurement/Read-Out cycles, the user registers can be changed with WR commands. Optionally
those registers can be read back with the RR command to check if the right values were uploaded.
Figure 19: Global timing diagram with separate SM-RO
Figure 20 shows a timing diagram wherein separate SM-RO cycles are mixed with combined SM-RO cycles. After the Power-
On-Reset phase, a SM measurement cycle is started. Once the DR pin is high, the data can be read out. A SM command with
extra clocks is used to combine the read-out and the start of the next measurement cycle. With the extra clocks, the data of
the internal registers is transferred to the MISO pin. When the CS pin goes high, the next measurement cycle (SM) will be
started.
Once the DR pin is high, a normal RO command is uploaded to bring the data to the MISO pin. If needed, the settings in the
user registers can be changed with the WR command and optionally the RR command can be used to check if the right
values were uploaded.
A new measurement cycle can be started with e.g. a normal SM command. When the DR pin is high, the data can be
transferred by uploading e.g. a SM command that combines the read-out and the start of a new measurement cycle.
POR
CS
SCLK
MOSI
MISO
DR
Device State
P OR
Internal Registers
(WR)
SM
SM
Output D ata
RO
Output Data
(WR)
SM
SM
Output Data
Id le
0
S M Measurement
Idle
Filling up
Data
A vailable
Read-out
S M Meas urement
Id le
E mpty ing
0
Filling up
D a ta
A vailable
Read-out
E mpty ing
Id le
S M Meas urement
Idle
R e ad-o ut
S M Measurement
Idle
0
Filling up
D ata
E mptying
0
Filling up
Data
A v ailable
A vailable
Figure 20: Global timing diagram with separate SM-RO and combined SM-RO together
REVISION 005 – DECEMBER 2013
3901075030
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