CP2400 SILABS [Silicon Laboratories], CP2400 Datasheet - Page 83

• Manufacturer Part Number: CP2400
• Description: 128/64 SEGMENT LCD DRIVER
• Manufacturer: SILABS [Silicon Laboratories]

12. LCD Segment Driver
CP2400/1/2/3 devices contain an LCD segment driver and on-chip bias generation that supports static, 2-mux, 3-
mux and 4-mux LCDs with 1/2 or 1/3 bias. The on-chip charge pump with programmable output voltage allows
software contrast control which is independent of the VDD supply voltage. LCD timing is derived from the
SmaRTClock oscillator to allow precise control over the refresh rate. A low frequency clock present on the CLK pin
may also be used as the LCD clock source.
The CP2400/1/2/3 contains on-chip ULP memory to store the enabled/disabled state of individual LCD segments.
All LCD waveforms are generated on-chip and software only needs to access the ULP memory to change the
information displayed on the LCD. An LCD blinking function is also supported. A block diagram of the LCD
segment driver is shown in Figure 12.1.
12.1. Initializing the LCD Segment Driver
The following procedure is recommended for using the LCD Segment Driver:
XTAL1
XTAL2
CLK
1. Configure the LCD size, mux mode, and bias using the LCD0CN register.
2. Configure the Port I/O pins to be used for LCD as Analog I/O.
3. Set the LCD contrast using the CONTRAST register.
4. Write the reserved value of 0x9F to LCD0CF.
5. Set the LCD refresh rate using the LCD0DIVH:LCD0DIVL registers.
6. Set the LCD toggle rate using the LCD0TOGR register.
7. Set the LCD power mode using the LCD0PWR register.
8. Write a pattern to the ULP memory.
9. Enable the LCD using the master control (MSCN) register.
SmaRTClock
Figure 12.1. LCD Segment Driver Block Diagram
RTCBYP
Charge
VDD
Pump
Configuration
Registers
Rev. 1.0
CPBYP
LCD State Machine
CAP
ULP Memory
10 uF
Generator
LCD Segment Driver
Bias
CP2400/1/2/3
Drivers
Port
4 COM Pins
Segment
Pins
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