Panasonic KX-TCD420GS, Service Manual, Page: 75 / 129

Pin Description I/O Hi Hi-z Remarks
87 LCD_SEGMENT D.O Active - -
88 (NO USE) D.O - -
89 Power Select D.O Low Power - -
90 LCD_SEGMENT D.O Active - -
91 LCD_SEGMENT D.O Active - -
92 LCD_SEGMENT D.O Active - -
93 LCD_SEGMENT D.O Active - -
94 LCD_SEGMENT D.O Active - -
95 LCD_SEGMENT D.O Active - -
96 LCD_SEGMENT D.O Active - -
97 LCD_SEGMENT D.O Active - -
98 LCD_SEGMENT D.O Active - -
99 LCD_SEGMENT D.O Active - -
100 LCD_SEGMENT D.O Active - -
27. EEPROM LAYOUT (BASE UNIT)
27.1. Scope
The purpose of this section is to describe the layout of the EEPROM (IC1) for the KX-TCD420 Base
Unit.
The EEPROM contains hardware, software, and user specific parameters. Some parameters are set
during production of the base e.g. crystal frequency adjustment at address 0000 and 0001, some are
set by the user configuration e.g. ringer volume at address 0220, and some are set during normal use
of the phone e.g. meter pulse billing at address 0140..015F.
27.2. Introduction
The base unit uses a 32K bit serial EEPROM (IC1) for storing volatile parameters. All parameters are
set up before the base leaves the factory. Some of these are vital for the operation of the hardware so
a set of default parameters is programmed before the actual hardware fine-tuning can be initiated.
This document lists all default settings with a short description.
In the tables below values in a range that are similar are not repeated; i.e. Address 00 to 01 contains
the value 00 simply means that the value 00 is repeated in all addresses in the range. All values in this
document are in hexadecimal notation.
Type Name Description
D default The EEPROM location is preset to the Default value by the eeprom default loader
A adjust
The EEPROM location is set during the production test and should not be
overwritten. The value is set by the eeprom default loader only if the location
contains all 1’s (byte: 0xFF, word FFFFh), i, e. it has never been set.
- EEPROM location which is not set at all.
d default Same as D but best-guess value and/or not verified.
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