MLX75030 Datasheet, PDF (36/72 Pages) Melexis Microelectronic Systems – Universal ActiveLight Sensor Interface

MLX75030 Universal ActiveLight Sensor Interface
Datasheet
7.2.2.8. SM+RO - Start Measurement combined with Read-Out
If after upload of the SM command, extra clocks are given (without putting CS high!), the data stored in the internal registers
will appear on the MISO pin. At the end of the read-out phase the internal registers will be cleared to avoid memory effects
in the next read-outs.
The newly uploaded SM command will be executed after the read-out, when the CS pin goes high.
The two figures below show the difference between the two modes of operation :
- Figure 13 : Separated SM - RO (X value is defined in Figure 6)shows the operation with separate SM and RO commands.
After upload of a SM command, the measurement cycle will start and the internal registers will be filled. Once the DR pin is
high, the RO command can be uploaded to start the read-out cycle. All data of the internal registers will be transferred and
at the end of the read-out the registers will be cleared.
- Figure 14 : Combined SM - RO (X value is defined in Figure 6) shows the operation with the combined SM and RO. First one
has to upload a SM command to start a measurement. The data is available for read-out when the DR pin goes high. Instead
of uploading a RO command, a SM command can be uploaded again to combine read-out and the start of the next
measurement cycle. If extra clocks are given after upload of the SM command, the data of the internal registers becomes
available on the MISO pin. Note that the CS pin shall not be set high until the read-out is finished. Once CS pin goes high, the
DR pin is set low and a new measurement cycle will be started. A time t_dr later the DR pin goes high to indicate that the data
is available.
CS
SCLK
MOSI
MISO ^{Tri state}
DR
Device State
Internal Registers
8tsclk
SM/ SD
S tatus Flags
1 byte
Idle
0x00
8tsclk
0x00
Ctrl 1
1 byte
tcs _dr
Tri state
tdr
Measurement Cycle
Filling up
8tsclk
8tsclk
R O- C tr l1
S tatus Flags
1 byte
RO-Ctrl 2
C tr l1
1 byte
Idle
Data Available
X*8tsclk
Output Data Frame
X bytes
Read-out
Emptying
Figure 13 : Separated SM - RO (X value is defined in Figure 6)
Tri state
Idle
0 x00
CS
SCLK
MOSI
MISO ^{Tri state}
DR
Device State
Internal Registers
8tsclk
SM/ SD
S tatus Flags
1 byte
Idle
0x00
8tsclk
0x00
Ctrl 1
1 byte
tcs _dr
Tri state
tdr
Measurement Cycle
Filling up
8tsclk
8tsclk
SM/ SD
S tatus Flags
1 byte
0x00
C tr l1
1 byte
Idle
Data Available
X*8tsclk
Output Data Frame
X bytes
Read-out
Emptying
Figure 14 : Combined SM - RO (X value is defined in Figure 6)
tcs_ dr
Tri state
tdr
Measurement Cycle
Idle
0x
00
Filling up
Data Available
REVISION 005 – DECEMBER 2013
3901075030
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