Panel Connector - Intel PXA27 Series Design Manual

LCD system design is not considered critical as infrequent or single bit errors are, typically, not
noticed by the user. Also, the errors are transitory, as the old data is constantly being replaced with
new data. Slower panel refresh rates increase the likelihood that a single error is noticed by the
user. However, there is a counteracting effect in that slower refresh rates relax LCD timing and,
therefore, result in fewer screen transmission errors. This is not the case for panels with internal
frame buffers as the data is transmitted to and then stored by the panel. This results in single bit
errors remaining until the screen changes and the incorrect bit being replaced. There are other
factors related to choosing a refresh rate for an LCD system, most significant is the impact on
system bandwidth. Refer to the section on "Bandwidth Calculations" in the Intel
Processor Family Developers Manual for more information.
If excessively long or poorly routed signals are used, one possible solution is to add buffers
between the PXA27x processor and the LCD panel. This helps strengthen the LCD panel signal
levels and synchronizes signal timing. However, this is usually not required as the LCD panel
timings are fairly relaxed. Since the LCD display essentially operates asynchronously from the
processor, the propagation delay of the buffers is not a significant concern.
7.4.4

Panel Connector

Most LCD panels are connected to the system board using a connector, instead of directly mounted
on the system board. Connecting the LCD panel to the system board using a connector increases
flexibility and makes it easier for the manufacturer. Typically, the manufacturer of the panel
recommends a particular connector for the panel. Follow the recommendations of the
manufacturer.
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Intel PXA27x Processor Family Design Guide
LCD Interface
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PXA27x
II:7-5