GreenPAK brings a wide range of integrated benefits to Liquid Crystal Displays (LCD) which are widely used for commercial and industrial applications because of their good visual properties, low cost, and low power consumption. These properties make the LCD the standard solution for battery-operated devices, like portable instruments, calculators, watches, radios, etc.

Unique combination of the most prevalent functions in small LCD equipped devices

  • LCD driver for multiplexed 4-com x 7(8)-segment displays
  • Watchdog
  • 8-byte RAM
  • Long-button-press reset/ship-mode control
  • Flexible character generation in BLE SW

Moreover, such devices have an unmatched small PCB footprint and can be built on any GreenPAK IC with an I2C interface.

GreenPAK Benefits for LCD Driver

GreenPAK Enhances Customization

  • Flexible character generation in system MCU
  • Easy customization of watchdog timer and reset function
  • GreenPAK GPIO routing is flexible ensuring the least complexity in PCB routing

GreenPAK Maximizes GPIO Flexibility

  • Flexible signal routing – PCB layout and routing
  • Configurable I/O – Pull-up/down resistors, Push-Pull, Open drain, etc.
  • Customizable logic – Active-low/high
LCD Driver

LCD Drive

LCD’s common and segment signals are synchronized in time by the internal oscillator. The Common signals are generated using the DFF chain and require external resistors to output three voltage levels. Segment signals are generated by cycling through the I2C configurable ASM.

LCD Drive

LCD Drive

System Monitor Functionalities

In addition to driving the LCD, system monitor functionalities such as watchdog timer, long-button press reset, and 8-byte RAM storage are available on the same chip. According to the application, the user can configure timings for the watchdog timer and long-button press reset.

Hardware Reset and Watchdog Timer

Hardware Reset and Watchdog Timer

Key Design Considerations:

  • LCD Voltage Range
    Operating voltage range varies with type of LCD
  • LCD Speed
    Use smaller resistors and stronger GPIO structures for generating voltage levels of common signals
  • Current Consumption
    If low current is required, then a low power mode can be implemented by turning OFF the internal oscillator and ACMP when the display isn’t needed or use an external switch to power the voltage regulator
  • I2C Speed
    GreenPAK I2C is 400kHz
  • I2C Address
    GreenPAK I2C can have up to 16 unique addresses
  • ASM 
    ASM’s RAM can be configured to display various patterns

Resource Utilization

SLG46537V/M-GreenPAK 5 device can integrate LCD driving along with system monitoring functionalities such as a watchdog timer, a long-button press reset, and 8-byte RAM storage into the same chip.

Documentation
Type Title Date
Application Note
AN-CM-276 System Monitor 4-MUX LCD Driver Solution
PDF 937 KB
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