ARM ARM DUI 0224I manual Switchedvddneg

Models: ARM DUI 0224I

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CLCD Display and Adaptor Board

SWITCHED_VDD_NEG

This –5V to –28V supply is generated from 5V. It can be enabled by

VDDNEGSWITCH in SYS_CLCD or permanently enabled by link 14.

SWITCHED_VDD_POS

This 11V to 28V supply is generated from 5V. It can be controlled by the touchscreen D/A converter or manually with a pot. It can be enabled by VDDPOSSWITCH in SYS_CLCD or permanently enabled by link 11. This supply is used to generate the STN bias voltage.

LCD_IO_VDD and Buffer I/O voltage

This is the voltage to the interface logic on the adaptor board and the display. Link 16 selects the adaptor board interface level as CLPWR or FIXED. Link 3 selects the display interface level as SWITCHED_FIXED or SWITCHED_CLPWR.

Caution

Link 3 and link 16 must be set to use the same power source.

INV_IO This is the voltage to the interface logic on the prototype board. Link 2 selects the level as 5V or 3.3V.

Note

The I/O signals to the CLCD adaptor board pass through tri-state buffers. The buffers must be powered from the same IO voltage as that required by the CLCD. This enables the translation of the IO signals from the 3V3 signal levels present on the PB926EJ-S. The buffers are enabled by LCDIOON in SYS_CLCD.

Figure C-6 on page C-10 shows the block diagram of the adaptor board power-control circuitry.

C-8

Copyright © 2003-2010 ARM Limited. All rights reserved.

ARM DUI 0224I

Page 326
Image 326
ARM ARM DUI 0224I manual Switchedvddneg