MLX75031 Datasheet, PDF (36/67 Pages) Melexis Microelectronic Systems – Optical Gesture & Proximity Sensing IC

MLX75031
Optical Gesture & Proximity Sensing IC
with Integrated LED Drivers
Datasheet
Byte 13
Temperature of LED that was fired (8 MSB)
Depends on EN_LEDSENS +
LED selection depends on
M3/M2
Byte 14
Temperature of LED that was fired (8 LSB)
Depends on EN_LEDSENS +
LED selection depends on
M3/M2
Byte 15
CRC (8 bit)
Output always
Table 19 : SM Output Data Frame - Measurement Sequence 2
When certain measurement blocks are disabled, the corresponding data bytes are omitted from the Output
Data Frame.
Cyclic Redundancy Check Calculation
In all Output Data Frames, a CRC byte is included as last byte. This byte provides a way to detect
transmission errors between slave and master. An easy method to check if there were no transmission
errors is to calculate the CRC of the whole read-out frame as defined in previous tables. When the
calculated CRC results in 0x00, the transmission was error free. If the resulting CRC is not equal to zero, then
an error occurred in the transmission and all the data should be ignored.
For more information regarding the CRC calculation, please refer to Section 8.18.
8.11.6. DM+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 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 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
tdr later the DR pin goes high to indicate that the data is available.
REVISION 001 – JANUARY, 2013
39010xxxxx
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