UM10744
OM13500 & OM13500A, PCA9620 & PCx8537 demo board
Rev. 1 — 23.September 2013
User manual
Document information
Info
Content
Keywords
Abstract
LCD, Liquid Crystal Display, LCD driver, segment driver, PCA9620,
PCF8537, PCA8537, LPCXpresso, Vertical Alignment (VA)
The OM13500 is an LCD demo board which can be used to demonstrate
and evaluate the PCA9620 segment driver. The OM13500A is the same
board, but instead of PCA9620, PCA8537 is mounted. The latter has a
reduced number of segment outputs and therefore is not able to drive all
display elements of the display on the board. The only affected part is the
dot matrix area on the display.
The board is controlled by an LPCXpresso micro controller board, which
contains the LPC1115, a Cortex M0 controller. A free IDE can be
downloaded in order to modify the software.
Supply of the board can be via two AA batteries, an AC adapter or USB.
NXP Semiconductors
UM10744
OM13500 & OM13500A user manual
Revision history
Rev
Date
1
20130923
Description
Initial version
Contact information
For more information, please visit:
http://www.nxp.com
For sales office addresses, please send an email to:
salesaddresses@nxp.com
UM10744
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2013. All rights reserved.
User manual
Rev. 1 — 23.September 2013
2 of 14
NXP Semiconductors
UM10744
OM13500 & OM13500A user manual
1. Introduction
This user manual describes the OM13500 and OM13500A demo boards. The boards
consist of a base board, with a plugged in LPCXpresso board which contains the
microcontroller to control the display driver. OM13500 and OM13500A are essentially the
same. The difference lies only in the segment driver which is mounted on the board. Only
one driver can be mounted. For OM13500 this is the PCA9620. The PCA9620 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 eight backplanes, 60 segments and up to 480 display elements. On the
OM13500A, PCA8537BH is used instead. This driver generates the drive signals for any
static or multiplexed LCD containing up to eight backplanes, 46 segments and 352
elements. Both display drivers are compatible with most microprocessors or
2
microcontrollers. PCA9620 communicates via a two-line bidirectional I C-bus. The
PCA8537 can be easily connected to a microcontroller by either the two line I
2
C-bus
(PCA8537AH) or a three-line bidirectional SPI-bus (PCA8537BH). Communication
overheads are minimized using a display RAM with auto-incremented addressing and
display memory switching. Both PCA9620 and PCA8537 feature an internal charge
pump for on-chip generation of the LCD driving voltages. To ensure an optimal and
stable contrast over the full temperature range, also a programmable temperature
compensation has been included.
This board was developed in order to provide a low cost tool to engineers, wishing to
demonstrate and evaluate these LCD drivers, and to get hands-on experience with
writing code for these drivers. Code written using this board can serve as an example for
the final application. This enables rapid prototyping.
Features:
•
Demonstrates PCA9620 (LQFP80) or PCA8537 (TQFP64) LCD driver
•
Features a vertical alignment (VA) display module with integrated backlight
•
Plugged in OM13035 LPCXpresso board with LPC1115 microcontroller
•
3 push buttons
•
User modifiable firmware, In-System/In-Application Programming (ISP/IAP) via
USB.
•
Power supply can be either using 2 AA-batteries, via USB or via an AC
adapter/external power supply. This can also be used for external V
LCD
.
•
Box contents:
o
OM13500 or OM13500A board (marked on the board)
o
OM13035 LPCXpresso board
The 12nc of the OM13500 board is:
9353 014 42598
UM10744
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2013. All rights reserved.
User manual
Rev. 1 — 23.September 2013
3 of 14
NXP Semiconductors
UM10744
OM13500 & OM13500A user manual
2. Board description and layout
Fig 1
shows the top view of the board.
Fig 1.
Top view of OM13500 demo board
For best optical performance, remove the protective foil from the display.
UM10744
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2013. All rights reserved.
User manual
Rev. 1 — 23.September 2013
4 of 14
NXP Semiconductors
UM10744
OM13500 & OM13500A user manual
On the board, below the NXP logo, is indicated which version of the board (OM13500
with PCA9620 or OM13500A with PCA8537) it is. The LCD driver positions are located
on the reverse side of the PCB, below the LCD. This location was chosen for layout
reasons, as it results in shorter traces from the driver to the LCD.
2.1 Power Supply
The schematic diagram of the board is shown in
Fig 2.
Besides applying power via the plugged in LPCXpresso board, there are three ways to
provide power to the base board:
1. Via mini-USB connector P1. Now the 5V come directly from the USB port.
2. Using two AA batteries. An on-board switching regulator, built around IC4,
generates 5V (5V_Bat). Whenever the batteries are inserted this regulator is
running. The current consumption at no load is very low, in the order of 20 µA.
Nevertheless, it is advisable to remove the jumper labeled “VBAT” when the
board will not be used for a longer time while the batteries are inserted. This will
interrupt the connection between batteries and switching regulator.
3. Via an external AC/DC adapter or DC power supply. The voltage may be in the
range from 7 V to 18 V. For the adapter a plug CON1 has been provided, where
the internal pin is +. It is also possible to connect the voltage to two pins (P3)
using a DC power supply. A diode protects against damage in case of wrong
polarity. Two linear regulators (IC1 and IC2) provide 5V (5V_ext) and the
external V
LCD
voltage VLCD_EXT, in case the internal charge pump is not used.
This external voltage VLCD_EXT can be adjusted using potentiometer POT1.
PCA9620 and PCA8537 include a temperature compensated internal V
LCD
generator.
The third power supply option allows switching quickly between an external supplied or
internal generated V
LCD
. This is useful for evaluating the optical performance as a
function of the voltage V
LCD
, as the external supplied voltage can be varied quickly using
potentiometer POT1. If the external V
LCD
supply option is used also jumper J1 must be
placed. Also the internal charge pump must be disabled.
Switch SW1 is used to select which of the three power supply options is being selected
(5V_BAT, 5V_USB or 5V_EXT). The 5V output of the switch is used to supply the
backlight of the display. Furthermore the voltage labeled “3V3_LPCXPR” is generated
with an additional regulator, IC5. The 3.3V are used to supply the microcontroller board
LPCXpresso, and to supply the logic V
DD
of the LCD driver.
The LPCXpresso board contains a JTAG/SWD debugger called the “LPC-Link” and a
target MCU. LPC-Link is equipped with a 10-pin JTAG header and it seamlessly
connects to the target via USB (the USB interface and other debug features are provided
by NXP’s ARM9 based LPC3154 MCU). When the firmware needs to be updated, the
LPCXpresso board will be connected using the USB to the computer on which the IDE is
installed. In this case, a 3.3V supply is generated on the LPCXpresso board via a linear
regulator which is integrated in the LPC3154. However, this regulator has limited current
delivery capability. If the LPCXpresso board is connected via USB to a computer without
any other supply to the base board, the 3.3V from the LPCXpresso board is used to
supply also the LCD base board. In this case the backlight will have limited intensity, but
enough to see the result of software changes. Supply is via diode D2 and resistor R9.
UM10744
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2013. All rights reserved.
User manual
Rev. 1 — 23.September 2013
5 of 14
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