SBOS993A December 2021 – December 2022 OPT4001
PRODUCTION DATA
Output registers always contain the most recent light measurement. Along with output registers there are 3 more shadow registers which have the data from the previous 3 measurements. For every new measurement, the data on the 3 shadow registers are updated to contain the most recent measurements discarding the oldest measurement similar to a FIFO scheme. These shadow registers along with output registers act like a FIFO with a depth of 4. The INT pin (only on SOT-5X3 variant) can be configured as shown in the figure below to generate an interrupt every measurement or can be configured to generate an interrupt every 4 measurements using the register INT_CFG. This way the controller reading data from OPT4001 device can minimize the number of interrupts by a factor of 4 and still get access to all the four measurements between the interrupts. By using the Burst Read Mode the output and FIFO registers can be read out with minimal I2C clocks.