Dell app177 Schematics

App Note 177

Programming 1-Wire EPROM and

EEPROM Memory Devices Using a PC

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INTRODUCTION

Dallas Semiconductor offers hardware/software solutions for programming DS243x series EEPROM and
DS250x series EPROM devices (or the DS197x and DS198x iButton® form factors) in a PC-based
environment. While these devices are commonly programmed in an embedded application, it is often
desirable or necessary to preprogram devices with data for prototyping purposes. An easy-to-use PC­based platform simplifies this task and is the scope of this document.

HARDWARE REQUIREMENTS

Shown in Figure 1 is a typical PC based Hardware configuration for 1-Wire® EEPROM and EPROM
programming. Required items include a WindowsÒ (98, 95, ME, 2K) based PC with a spare serial (COM)
port, a Dallas Semiconductor serial to 1-Wire port adapter, and cabling to attach 1-Wire devices for
programming.

PC-BASED PROGRAMMING CONFIGURATION Figure 1

Target HW with 1-Wire

Host PC Running

TMEX-Based Utilities

from Dallas

Semiconductor

Data Cable

EPROM or EEPROM to be

Programmed or R/W

DS9097U-E25
Adapter

AC Adapter or DC

Power for

DS9097U-E25

Dallas Semiconductor offers a variety of adapters that convert Serial COM port communication to 1-Wire
waveforms and protocol. See Table 1 for a comparison of port adapter capabilities relative to
EEPROM/EPROM reading and programming. The DS9097U are the current generation adapters. The
DS9097U-009 and the DS9097U-S09 are the recommended models for EEPROM programming. The
DS9097U-E25 is the recommended model for EPROM programming. Figure 2 shows the DS9097U-E25
package and the connector pinouts. The RJ-11 pinout applies to all port adapters in Table 1.

1-WIRE SERIAL PORT ADAPTERS Table 1

ADAPTER EEPROM R/W EPROM READ EPROM PROGRAM

DS9097U-009 X X
DS9097U-S09 X X
DS9097U-E25 X X X
DS9097E* X X X
* Not recommended for new projects.

iButton and 1-Wire are registered trademarks of Dallas Semiconductor.
Windows is a registered trademark of Microsoft Corporation.

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DS9097U-E25 1-WIRE SERIAL PORT ADAPTER AND +12V PINOUTS Figure 2

g

2.1mm Power Jack

- Contact

+ Contact

16234 5

RJ-11

TOP VIEW END VIEW

Return

RJ-11 Pinout

Lookin

into the Socket

1-Wire

12VDC Power for EPROM Programming

Programming EPROMs requires the application of a +12VDC programming pulse. The DS9097U-E25
provides this capability when supplied with +12VDC power. As shown in Figure 2, a 2.1mm power jack is
used to attach either power from a bench supply or common AC wall adapter. Power jack polarity must
be observed: center contact is ground and outer contact is +12V. See EPROM data sheets for voltage
tolerance and current levels required to program devices. The following +12VDC wall adapter has been
successfully used to program devices:

§ Stancor # STA-300R

It can also be purchased from the following:

§ Allied (Stock #928-9895)

§ Newark (Stock #84F2081)

A schematic for a serial port-based adapter similar to the DS9097U-E25 that supports EPROM
programming is shown in Figure 3. This schematic can be used as a reference for developing an adapter
that will operate from an RS232 serial port. If +12V EPROM programming is not a requirement,
components R5-R7, D5, D6, and D9 can be eliminated and the DS2480B VPP signal (pin 5) must be
connected to VDD (pin 4).

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