EPROM's, the EP-1 Programmer and the EP Program

Prepared by Charles S. Tritt, Ph.D.
July 10, 1997

Background

This document is only an introduction to the EP-1 programmer and the EP program.  For more information see the EP-1 User's Manual that comes with the programmer.  This document applies to EP Software version 1.19 and EPROM Programmer version 3.11 both from BP Microsystems..

You can check out EPROM's and an EP-1 EPROM programmer from the EECS Technical Support Center (TSC).  The TSC has 16K, 32K, 64K, 128K and 512K bit chips in stock.  You can ask for data sheets for these chips at the TSC counter.  These chips are erased between uses by the TSC staff.  The EPROM programmer comes with instructions, a diskette and a RS-232 cable.

EPROMS sizes are generally specified in bits.  For example, a 512K EPROM contains 512 × 1024 = 524,288 bits.  Most of the EPROM's we have are one byte (8 bits) wide.  That is they have 8 output bits.  A 27512 EPROM has 524,288 / 8 = 65,536 byte or 65536 / 1024 = 64K bytes.  In the chip literature, this would be called a 64K × 8 chip.

You must tell the EP-1 the type of chip to be programmed during the programming process.  Chips generally have manufacture and model information on the tops of their packages.  Prefixes and suffixes are sometimes added to the numbers on the packages.  Generally, you should ignore these.  The exception is A or B suffixes.  These are important because they indicate the programming algorithm required by the chip.  For example, an Intel D2732A-3 would be programmed as an Intel 2732A.

Installing the Programmer

The only control on the EPROM programmer is a power switch.  The programmer is controlled using commands sent from a computer over a RS-232 (serial or COM port) connection.  To use the programmer you must find a MS-DOS PC with an accessible RS-232 port.  With the power off, connect the programmer to the PC with the RS-232 cable.  Turn on the power to the PC and the programmer.
 
Using the EP Program

The EP program comes with the EP-1 programmer.  This program is already installed on the hard disk drives of some PC's around the school.  Look for an EPROM directory.  If one exists, make it the default directory.  If there is no EPROM directory, insert the diskette that comes with the EPROM programmer in the A: drive and make it the default drive.  To start the program, enter: EP x.  Where x is the number of the COM port to which the programmer is connected.  A copyright message followed by a > prompt should be displayed on the screen at this point.
You can enter commands at EP's > prompt.  The most important commands are listed below.  Most of these commands can be abbreviated to just one or two letters.

BLANK		Verifies that a chip has been properly erased.
CHIP (or just C)	Allows specification (via menus) of the type of chip to be programmed.
HELP			Displays an inaccurate list of EP commands.
LIST b, e (or just L)	Displays the data stored in the chip where the optional b and e arguments specify the 			beginning and ending addresses (in Hex) to be listed.
P			Prompts you for a file type (B for Binary, H for Hex) and name and programs a chip based on its contents.
RH		Read the contents of a chip and save it in a file.  You will be prompted for a file type and name.
STATUS	Displays the status of the EP-1 programmer.

Use Ctrl-D to exit the EP software.  Use Ctrl-C to cancel a command.  Use Ctrl-S to toggle screen scrolling.

To program a chip you would generally use the following procedure:

Specify the type of chip you are programming with the CHIP command.
Insert a chip into the socket on the programmer in the correct orientation.
Verify that the chip has been properly erased using the BLANK command.
	Program the chip using the P command.
Remove the chip from the programmer.

Never remove a chip while the yellow Active light is on.  Never turn the programmer on or off with a chip in the socket.

File Formats

Binary files are stored in the EPROM byte by byte, exactly as they exist on disk.  The problem with this type of programming is that most 8-bit binary codes are not printable ASCII characters.  This makes creating and editing the file difficult.  Binary files are most useful for storing text data on a chip.

In Hex files, bytes are represented by hexadecimal numbers in ASCII form.  For example, the binary value 10011101 is written 9D.  There are several types of Hex files.  The EP program automatically recognizes each of these formats.  The two that you are likely to use are Straight Hex and Hex-space formats.  Straight Hex files consists pairs of hex characters (0-9, A-F) for each data byte.  The pairs are separated into lines with Carriage Return, Line Feed combinations.  Hex-space files are identical to straight hex files except that spaces may separate pairs of digits and more than one pair of digits may appear on a line.  Be sure the last line in your hex file ends with a CR/LF.  Lines not ending with CR/LF are ignored by the EP program.  Text after semicolons in hex files is ignored.