Datasheet
LPC11D14 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.
Product data sheet Rev. 2 — 23 July 2012 13 of 47
NXP Semiconductors
LPC11D14
32-bit ARM Cortex-M0 microcontroller
7. Functional description
7.1 LPC1114 microcontroller
See Ref. 1 for a detailed functional description of the LPC1114 microcontroller.
7.2 LCD driver
See Ref. 2 for a detailed functional description of the PCF8576D LCD driver.
7.2.1 General description
The PCF8576D is a peripheral device which interfaces to almost any Liquid Crystal
Display (LCD) with low multiplex rates. It generates the drive signals for any static or
multiplexed LCD containing up to four backplanes and up to 40 segments. It can be easily
cascaded for larger LCD applications. The PCF8576D communicates via the two-line
bidirectional I
2
C-bus. Communication overheads are minimized by a display RAM with
auto-incremented addressing, by hardware subaddressing and by display memory
switching (static and duplex drive modes). Please refer to PCF8576D data sheet for
electrical data.
7.2.2 Functional description
The PCF8576D is a versatile peripheral device interfacing the LPC1114 microcontroller
with a wide variety of LCDs. It can directly drive any static or multiplexed LCD containing
up to four backplanes and up to 40 segments.
The possible display configurations of the PCF8576D depend on the number of active
backplane outputs required. A selection of display configurations is shown in Table 4
. The
integration of the LPC1114 microcontroller with the PCF8576D is shown in Figure 1
.
7.2.3 Reset state of the LCD controller and pins
After power-on, the LCD controller resets to the following starting conditions:
• All backplane and segment outputs are set to V
LCD
.
• The selected drive mode is 1:4 multiplex with 1/3 bias.
• Blinking is switched off.
• Input and output bank selectors are reset.
• The I
2
C-bus interface is initialized.
• The data pointer and the subaddress counter are cleared (set to logic 0).
• The display is disabled.
Table 4. Selection of display configurations
Number of Digits/Characters
Backplanes Segments 7-segment 14-segment Dot matrix/Elements
4 160 20 10 160 (4 40)
3 120 15 7 120 (3 40)
2 80 10 5 64 (2 40)
1405240 (1 40)