SBOSA84 December   2022 OPT4048

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Spectral Matching to CIE
      2. 8.3.2 Automatic Full-Scale Range Setting
      3. 8.3.3 Output Register CRC and Counter
        1. 8.3.3.1 Output Sample Counter
        2. 8.3.3.2 Output CRC
        3. 8.3.3.3 Threshold Detection
      4. 8.3.4 Device Functional Modes
        1. 8.3.4.1 Modes of Operation
        2. 8.3.4.2 Interrupt Modes of Operation
        3. 8.3.4.3 Light Range Selection
        4. 8.3.4.4 Selecting Conversion Time
        5. 8.3.4.5 Light and Color Measurement
        6. 8.3.4.6 Light Resolution
        7. 8.3.4.7 Programming
          1. 8.3.4.7.1 I2C Bus Overview
            1. 8.3.4.7.1.1 Serial Bus Address
            2. 8.3.4.7.1.2 Serial Interface
          2. 8.3.4.7.2 Writing and Reading
            1. 8.3.4.7.2.1 High-Speed I2C Mode
            2. 8.3.4.7.2.2 Burst Read Mode
            3. 8.3.4.7.2.3 General-Call Reset Command
            4. 8.3.4.7.2.4 SMBus Alert Response
    4. 8.4 Register Maps
      1. 8.4.1 ALL Register Map
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Electrical Interface
      2. 9.2.2 Design Requirements
        1. 9.2.2.1 Optical Interface
      3. 9.2.3 Detailed Design Procedure
        1. 9.2.3.1 Optomechanical Design
      4. 9.2.4 Application Curves
    3. 9.3 Do's and Don'ts
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
      3. 9.5.3 Soldering and Handling Recommendations
  10. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.4.2 Interrupt Modes of Operation

The device has an interrupt reporting system that allows the processor connected to the I2C bus to go to sleep, or otherwise ignore the device results, until a user-defined event occurs that requires possible action. Alternatively, this same mechanism can also be used with any system that can take advantage of a single digital signal that indicates whether the light is above or below levels of interest.

Channel on which this behavior can be enabled is set by the register THRESHOLD_CH_SEL.

The INT pin has an open-drain output, which requires the use of a pull-up resistor. This open-drain output allows multiple devices with open-drain INT pins to be connected to the same line, thus creating a logical NOR or AND function between the devices. The polarity of the INT pin can be controlled by the INT_POL.

There are two major types of interrupt reporting mechanism modes: latched window comparison mode and transparent hysteresis comparison mode. The configuration register LATCH controls which of these two modes is used. Figure 8-2 and Table 8-1 summarize the function of these two modes. Additionally, the INT pin can either be used to indicate a fault in one of these modes (INT_CFG=0) or to indicate a conversion completion (INT_CFG >0). This is shown in Table 8-2.

GUID-20221115-SS0I-GP01-9G1V-JKHJWSF97PVC-low.png Figure 8-2 Interrupt Pin Status (for INT_CFG=0 setting) and Register Flag Behavior
Table 8-1 Interrupt Pin Status (for INT_CFG=0 setting) and Register Flag Behavior
LATCH Setting INT Pin State (when INT_CFG=0) FLAG_H Value FLAG_L Value Latching Behavior
0: Transparent hysteresis mode INT pin indicates if measurement is above (INT active) or below (INT inactive) the threshold. If measurement is between the high and low threshold values then the previous INT value is maintained. This prevents the INT pin from repeated toggling when the measurement values are close to the threshold. 0: If measurement is below the low limit
1: If measurement is above the high limit
If measurement is between high and low limits previous value is maintained		 0: If measurement is above the high limit
1: If measurement is below the low limit
If measurement is between high and low limits previous value is maintained		 Not latching: Values are updated after each conversion
1: Latched window mode INT pin becomes active if the measurement is outside the window (above high threshold or below the low threshold). The INT pin does not reset and return to the inactive state until register 0xC is read. 1: If measurement is above the high limit 1: If measurement is below the low limit Latching: INT pin, FLAG_H and FLAG_L values do not reset until the register 0x0C is read.

The THRESHOLD_H, THRESHOLD_L, LATCH and FAULT_COUNT registers control the interrupt behavior. The LATCH field setting allows a choice between the latched window mode and transparent hysteresis mode as shown in the table. Interrupt reporting can be observed on INT pin, the FLAG_H, and the FLAG_L registers.

Results from comparing the current sensor measurements with THRESHOLD_H and THRESHOLD_L registers are referred to as fault events. The calculations to set these registers can be found in Section 8.3.4.5. The FAULT_COUNT register dictates the number of continuous fault events required to trigger an interrupt event and subsequently change the state of the interrupt reporting mechanisms. For example, with a FAULT_COUNT value of 2 corresponding to 4 fault counts, the INT pin, FLAG_H and FLAG_L states shown in the table are not realized unless 4 consecutive measurements are taken that satisfy the fault condition.

INT pin function listed in Table 8-1 is valid only when INT_CFG=0. The INT pin function can be changed to indicate an end of conversion as well shown in Table 8-2. The FLAG_H and FLAG_L registers continue to behave as listed in Table 8-1 even while INT_CFG>0. The polarity of the INT pin is controlled by the INT_POL register.

Table 8-2 INT_CFG Setting and Resulting INT Pin Behavior
INT_CFG Setting INT Pin Function
0 As per Table 8-1
1 INT pin asserted with 1us pulse width after conversion of every channel
3 INT pin asserted with 1us pulse width every 4 conversions to indicate all channel measurements are complete