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 Windows (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
Host PC Running |
Target HW with 1-Wire |
EPROM or EEPROM to be |
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TMEX-Based Utilities |
Programmed or R/W |
from Dallas |
Data Cable |
Semiconductor |
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DS9097U-E25 |
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Adapter |
AC Adapter or DC |
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Power for |
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DS9097U-E25 |
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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 |
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DS9097U-S09 |
X |
X |
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DS9097U-E25 |
X |
X |
X |
DS9097E* |
X |
X |
X |
* Not recommended for new projects.
iButton and 1-Wire are registered trademarks of Dallas Semiconductor. |
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Windows is a registered trademark of Microsoft Corporation. |
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DS9097U-E25 1-WIRE SERIAL PORT ADAPTER AND +12V PINOUTS Figure 2
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2.1mm Power Jack |
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- Contact |
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+ Contact |
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1 |
2 |
3 |
4 |
5 |
6 |
RJ-11 |
Return |
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1-Wire |
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TOP VIEW |
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END VIEW |
RJ-11 Pinout |
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Looking into the Socket |
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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