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Mac Magazin/MacEasy 24
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Mac Magazin and MacEasy Magazine CD - Issue 24.iso
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Wissenschaft & Technik
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MacEEP
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MacEEP.txt
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1996-07-19
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5KB
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108 lines
MacEEP User's Guide
Introduction
This application is a Macintosh™ driver for the EEP-1 EEPROM programmer
described in the November 1995 issue of Electronics Now, page 37. In
addition to downloading binary files to the programmer, it has
facilities to upload programs from an EEPROM to a file, and create a
binary file from either an Intel Hex file or a Motorola™ S19 record.
The binary can then be downloaded to an EEPROM.
Use
Running the program is simple. After connecting the programmer your
Mac's serial port, simply launch the application. The menu and
graphical interface are selfexplanatory. If problems arise during
operation, error messages will be posted by means of Alert dialogs.
Interface
Connection to the EEP-1 is via the Mac's serial port. In Mac models
with both a printer port and a modem port, the modem port must be used.
The EEP-1 interface is RS-232. A standard Mac Mini-8 connector to
DB-25 modem cable should work in conjunction with a DE-9 male to DB-25
female adapter (e.g. Jameco part no. 10321). The connections are
between TXD-, pin 3 on the MIni-8 connector to pin 2 on the DB-25 and
RXD-, pin 5 in the Mini-8 to pin 3 on the DB-25. RXD+, pin 8 on the
Mini-8 is grounded through pin 7 on the DB-25.
A word of caution concerning the RS-232 interface is in order. The
serial interface on Macs use a the RS-423 standard, a balanced
interface. Ordinarily, this probably would not be of concern. However,
the DS1275 RS-232 transceiver used on the EEP-1 operates from a single
ended supply rail by robbing the RXIN line for the TXOUT marking state,
negative signal. When the Mac is transmitting to the EEP-1 and the RXIN
line transitions to a space, or high, there is no marking state signal
level to rob and the DS1275 circuitry pulls the TXOUT line weakly to
ground. In an RS-232 system this is of no real consequence because of
the relatively high thresholds in the RS-232 standard. But, the
threshold in the RS-423 standard is relatively low, and within
tolerances, the transition to ground may appear to the Mac as a mark to
space transition. The ideal solution is to put together a hardware
interface using an RS-232 transceiver that operates from a single ended
supply but generates the negative rail internally, such as the Maxim™
MAX232 or Dallas Semiconductor™ DS232, along with a pair of RS-422
interface chips like the 26LS30/26LS32. Nevertheless, the MacEEP
program attempts to anticipate this problem and work around it. In
doing this, it must run slower than it otherwise would.
Messages
Error conditions are signaled by Alert dialogs. MacEEP looks for echoes
sent by the EEP-1. If there is no echo when the software is expecting
one or the echo is different from that which the program expected, an
error message will be posted. If the EEP-1 is working properly, the
most likely cause of the problem is a bad interface connection. An
error of this type can also arise during the course of a download or an
erase if the EEPROM has one or more bad cells. When an operation is
complete, MacEEP will post a dialog telling you. During the operation,
there is nothing to tell you what is happening. However, the LED on the
EEP-1 is off while a download, upload or erase is taking place. If the
LED is off and no error message is posted, then the programmer is
functioning normally. When the task is completed, the LED will turn on.
So, the LED together with the Alerts signal the status of the
programmer.
Running Time
To download the 2048 bytes of a 2816 takes slightly more than one
minute.. Obviously downloading fewer bytes takes less time. Uploading
and erasing necessarily loop through the entire EEPROM so they also take
just over a minute. Larger EEPROMs woud take a proportionately longer
time.
Legal Stuff
Both the source code and object code of MacEEP is copyright by the
author, Barry S. Newberger, and is provided subject to the license
enclosed with the distribution. The software will not run if the
license is separated from the folder in which the application resides.
Registration fees should be sent to:
Barry S. Newberger
10037 Circleview Drive
Austin, TX 78733-6303
e-mail: bsn@mail.utexas.edu
Mamix™ is a registered trademark of Maxim Integrated Products, Dallas
Semiconductor™ is a registered trademark of Dallas Semiconcuctor
Corporation, and Motorola™ is a registered trademark of Motorola,
Incorporated. Macintosh™ is a registered trademark of Apple Computer,
Inc.
©1996, Barry S. Newberger