MLX75030 Datasheet, PDF (31/72 Pages) Melexis Microelectronic Systems – Universal ActiveLight Sensor Interface

MLX75030 Universal ActiveLight Sensor Interface
Datasheet
7.2.2.4. RSTBY/CSTBY - Request Standby/Confirm Standby
To put the device in Standby Mode, a similar system is used: the master shall send the RSTBY command, requesting the slave
to go into Standby Mode. The slave device sets bit 3 of the internal status flag byte high, indicating that it wants to go into
standby. The master has to confirm this by sending the CSTBY byte.
The status flag can be cleared by uploading a CR command or a NRM command.
Uploading a Chip Reset makes the device switching into normal running mode.
When the device is operating in Standby Mode, the WAKE_UP pin will be monitored. A falling edge on WAKE_UP will wake
up the device and will switch it into Normal Running Mode.
Note that no pull-up or pull-down resistor is foreseen on the WAKE_UP pin. To avoid that parasitic spikes can wake up the
device, the WAKE_UP input is debounced (typical debounce time is in the range of 2µs). The low time on the WAKE_UP pin
should be at least a time t_{wu_l}.
The state of the DR pin will not be changed when going into Standby Mode. However, after a wake-up event the DR pin is set
low during a time t_{wakeup_stby}.
7.2.2.5. NRM – Normal Running Mode
The NRM command shall be used to wake up the device from Sleep Mode, or to go from Standby into Normal Running
Mode. This requires a time t_{wakeup_slp} resp. t_{wakeup_stby} before the internal analog circuitry is fully set up again. The NRM will
also clear the Sleep Request or Standby Request flag.
When the NRM command is uploaded during normal running mode, the state of the device will not be influenced, except
when the Sleep Request or Standby Request flag was set high due to a RSLP or RSTBY command. In this case, the Sleep
Request or Standby Request flag will be cleared; the state of the DR pin will not change.
7.2.2.6. SM – Start Measurement
The SM command is used to start up measurement cycles. Several types of measurements can be selected with the
measurement selection bits M₆..M₀ in the Control2 Byte:
• M₆: setting this bit high enables the temperature measurement
• M₅: setting this bit high enables the read-out of the two ambient light channels
• M₄: setting this bit high enables the DC light measurement in the active light channel(s)
• M₃: setting this bit high fires LED A
• M₂: setting this bit high fires LED B
• M₁: setting this bit high enables the active light measurement in channel A
• M₀: setting this bit high enables the active light measurement in channel B
A typical timing diagram is given in Figure 11. After uploading the SM command, the measurement cycle is started as soon as
the CS pin is set high. The ADC starts converting all the needed analog voltages and stores the digital values in registers.
A time t_{cs_dr} after CS is set high, the state of the DR pin goes low. A time t_dr after DR was set low, the state of the DR pin
becomes high, indicating that all measurements are completed and that the resulted data is available for read-out (read-
back of the stored data in the registers). This time can be up to 231.84us, if an internal autozeroing process is under
execution and needs to be finished.
Table 14 : Example measurement execution times tdr gives an overview of some execution times t_dr for the basic types of
measurements.
REVISION 005 – DECEMBER 2013
3901075030
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