AN1924 Motorola / Freescale Semiconductor, AN1924 Datasheet - Page 4

• Manufacturer Part Number: AN1924
• Description: AN1924 Interfacing Serial LCDs to a DSP56F805s SCI and Porting Code Using the Embedded SDK
• Manufacturer: Motorola / Freescale Semiconductor

Descriptions of the Intelligent LCD Modules
3.1
3.2 NetMedia’s LCD+ Serial LCD Module
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This LCD module has attracted attention for its capability of interfacing as either an RS-232 device or
as an SPI device. As it comes from the factory, it is set up for 9600 Baud RS-232 operation. To use it
as an SPI device, the Jumper JPA must be soldered closed. However, the throughput of the LCD’s SPI
port is very slow (F
slow speed without extraordinary manipulation of the DSP chip’s clocking rate. Therefore, interface as
an RS-232 device is recommended.
These are the features of the 634:
A microcontroller is built into the LCD’s support and a ROM stores the necessary code for its
operation. Further information is available from Crystalfontz’s web site: www.crystalfontz.com.
Figure 3
NetMedia’s intelligent LCD was featured in the application note, “General DSP568xx Interface
Examples Using the Embedded SDK”, AN1921/D. The LCD+ comes with a 20x4 display and a
built-in port capable of supporting a keypad up to 4x4 in size. It supports an RS-232 interface that can
work at either normal or TTL voltage levels.
Crystalfontz’s 634 Intelligent Serial LCD Module
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RS-232 interface (1200, 2400, 4800, and 9600 Baud)
DB9 connector provided for a simple RS-232 hookup
Available with bright, even, software-adjustable LED backlighting or in a low-power
reflective model
Available as either 20x4 (Model 634) or 16x2 (Model 632) display
Software-controlled contrast
“Gapless” horizontal contrast
Software-controlled, terminal-style automatic scrolling and line wrapping
Unique “Scrolling Marquees” feature continuously scrolls a message across the display
without host intervention
Low-speed “SPI” and “Inverted TTL” RS-232 for embedded application
Buffered communication
Low power: Non-backlight operation will self-power from the DTR and RTS lines of most
serial ports
shows the 634’s display on power-up.
Figure 3. Crystalfontz’s 634 Intelligent Serial LCD Module Display
clk.max
=18 kHz) and SPI ports on the DSP56F80x family are incapable of such
Interfacing LCDs and Porting Code