SNVS256E November   2003  – October 2024 LP3943

PRODUCTION DATA  

  1.   1
  2. 1Features
  3. 2Applications
  4. 3Description
  5. 4Pin Configuration and Functions
    1.     Pin Functions
  6. 5Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 I2C Interface (SCL and SDA Pins) Timing Requirements
    7. 5.7 Typical Characteristic
  7. 6Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
    4. 6.4 Device Functional Modes
    5. 6.5 Programming
      1. 6.5.1 I2C Data Validity
      2. 6.5.2 I2C START and STOP Conditions
      3. 6.5.3 Transferring Data
      4. 6.5.4 Auto Increment
    6. 6.6 Register Maps
      1. 6.6.1 Binary Format for Input Registers (Read-only)—Address 0x00 and 0x01
      2. 6.6.2 Binary Format for Frequency Prescaler and PWM Registers — Address 0x02 to 0x05
      3. 6.6.3 Binary Format for Selector Registers — Address 0x06 to 0x09
  8.   Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Reducing IQ When LEDs are OFF
      3. 7.2.3 Application Curve
    3. 7.3 System Examples
    4. 7.4 Power Supply Recommendations
    5. 7.5 Layout
      1. 7.5.1 Layout Guidelines
      2. 7.5.2 Layout Example
  9. 7Device and Documentation Support
    1. 7.1 Receiving Notification of Documentation Updates
    2. 7.2 Community Resources
    3. 7.3 Trademarks
  10. 8Revision History
  11.   Mechanical, Packaging, and Orderable Information

6.6.3 Binary Format for Selector Registers — Address 0x06 to 0x09

Table 6-8 Address 0x06 (LS0)
Bit #76543210
Default value00000000
B1B0B1B0B1B0B1B0
LED3LED2LED1LED0
Table 6-9 Address 0x07 (LS1)
Bit #76543210
Default value00000000
B1B0B1B0B1B0B1B0
LED7LED6LED5LED4
Table 6-10 Address 0x08 (LS2)
Bit #76543210
Default value00000000
B1B0B1B0B1B0B1B0
LED11LED10LED9LED8
Table 6-11 Address 0x09 (LS3)
Bit #76543210
Default value00000000
B1B0B1B0B1B0B1B0
LED15LED14LED13LED12
Table 6-12 LED States With Respect To Values in B1 and B0
B1B0Function
00Output Hi-Z
(LED off)
01Output LOW
(LED on)
10Output dims
(DIM0 rate)
11Output dims
(DIM1 rate)

Programming Example:

  • Dim LEDs 0 to 7 at 1Hz at 25% duty cycle
  • Dim LEDs 8 to 12 at 5Hz at 50% duty cycle
  • Set LEDs 13, 14 and 15 off
  • Step 1: Set PSC0 to achieve DIM0 of 1 s
  • Step 2: Set PWM0 duty cycle to 25%
  • Step 3: Set PSC1 to achieve DIM1 of 0.2 s
  • Step 4: Set PWM1 duty cycle to 50%
  • Step 5: Set LEDs 13, 14 and 15 off by loading the data into LS3 register
  • Step 6: Set LEDs 0 to 7 to point to DIM0
  • Step 7: Set LEDs 8 to 12 to point to DIM1
Table 6-13 Programming Details
STEPDESCRIPTIONREGISTER NAMESET TO (HEX)
1Set DIM0 = 1 s
1 = (PSC0 + 1)/160
PSC0 = 159		PSC00x09F
2Set duty cycle to 25%
Duty Cycle = PWM0/256
PWM0 = 64		PWM00x40
3Set DIM1 = 0.2s
0.2 = (PSC1 + 1)/160
PSC1 = 31		PSC10x1F
4Set duty cycle to 50%
Duty Cycle = PWM1/256
PWM1 = 128		PWM10x80
5LEDs 13, 14 and 15 off
Output = HIGH		LS30x03
6LEDs 0 to 7
Output = DIM0		LS0, LS1LS0 = 0xAA
LS1 = 0xAA
7LEDs 8 to 12
Output = DIM1		LS2, LS3LS2 = 0xFF
LS3 = 0x03