INTRODUCTION

The EPROM (Erasable Programmable Read Only Memory) receives it's name because it is a ROM that's bit pattern can be changed using an EPROM Programmer.  This feature allows the user to erase and program them as many times as they want giving the EPROM a main advantage over regular ROMs.  The process of erasing the EPROM usually consists of shining Ultraviolet light through a transparent plastic window found on most EPROMs.  For CMPH 227 we will be using the Chip Master 6000 for the programmer (See above photograph).

DEFINITION

Read Only Memories are ICs used to store information permanently.  Usually data stored on ROMs is unchangeable so if changes need to be made or there was a mistake in the initial programming one would have to get a new ROM to write to.  The EPROM on the other hand allows the information to be erased and rewritten.  One advantage to using Read Only Memories is that they are non-volatile, meaning that they do not lose their information when power is removed.

ERASING AN EPROM CHIP

An EPROM erasing, ultra-violet lamp is used to erase the EPROM.  The chip is placed into the lamp which floods it with extreme amounts of ultra-violet light changing all the memory locations/addresses high.  This change clears the chip of it's previous program.  An EPROM chip cannot be programmed unless it is blank/clear with all memory locations/addresses set high.  The entire process of erasing the chip takes approximately 20-30 minutes while it only takes 100 seconds to program an 8 bit EPROM.  This time difference is because the CM6000 downloads the program into local memory, then an on-board microprocessor programs the EPROM.

CM6000 FUNCTIONS

Some of the special features of the CM6000:

• Reads devices for faults
• Reads the "silicon signature" or "device identifier" to determine vendor and product number of the inserted device
• Automatically identifies information about the inserted EPROM
• Automates EPROM and flash memory ID detection
• Acts as a ROM emulator. Can simulate a 128 x 8 ROM or 512 x 8K ROM (if upgradeable) Access time is 100 nsec
• Able to apply Vcc, GND, Vpp, Clk, TTL and tri-state to any of it's pins
• Reads the high/low voltage points of an EPROM
• Capable of programming any device that falls within it's pin range (48 pin max.)

• Invalid devices (useless or damaged pins)
• upside-down insertion
• Faulty devices
• Poor pin contacts

KEYS YOU SHOULD KNOW

Although there are more keys these are the ones you will need to know for the lab.

        EDIT: this is where you go to edit the program you will be putting on the chip.

        BLANK: performs a blank check on the chip.

        READ: reads the contents from the socketed chip, the one in the eprom burner, into the memory buffer.

        PROGRAM: burns the program that you have selected, onto the EPROM.

        VERIFY: checks that memory on the chip is the same as that in the memory buffer.

        COMPARE: basically the same thing as the VERIFY command, so guess what, you only have to pick one of these to use.

EPROM BURNER LAB

When you think you are ready proceed to the EPROM lab.

EPROM BURNER LAB

MULTPLE CHOICE QUESTIONS