MEMORY PLUS Manual By Lee Davison

				EPROM Programming

	The usefulness of the EPROMs on the MEMORY PLUS board is enhanced by the
	inclusion of on board EPROM programming facilities.  The INTEL 2716 EPROM
	is electrically programmable and ultraviolet light erasable.  The user can
	buy or build an ultraviolet light eraser.  MEMORY PLUS provides the parts
	required for the programming of the EPROMs.  These parts consist of the
	following items:

	  EPROM Programming Socket:  Socket 79 is a 24 pin socket located toward
		the lower right hand corner of the board.  The EPROM to be
		programmed is placed in this socket.

	  +25 Volt Regulator:  +25 volts is required for programming the 2716.
		This may be provided directly by the user at pin A-22 of the
		MEMORY PLUS application connector.  Since this voltage is so
		critical, and since an over voltage can destroy an EPROM, an
		on board regulator circuit is provided.  This will provide about
		24.7 volts when supplied with +27 to +30 volts at pin E-3 of the
		MEMORY PLUS expansion connector.

	  Control Lines:  The EPROM requires eleven (11) address lines, eight (8)
		data lines, and two (2) control lines.  All but three of these
		lines are provided by the MEMORY PLUS VIA 6522.  The remaining
		three lines come from the MICRO port B: PBO, PB1, and PB2.

	  Timing:  EPROM programming requires a 50 millisecond pulse be applied
		to the EPROM.  The VIA 6522 includes a timer which is used for
		timing this interval.

	  EPROM Programming Program:  The control of the programming is handled
		by a program run on the MICRO.  This program is provided in the
		form of a source listing in this manual and as a cassette tape
		included in the MEMORY PLUS package.

	The 2716 EPROM may be programmed one location (byte) at a time, or the entire
	EPROM may be programmed.  The steps required to program the EPROM are:

	  1.	With the power off, insert the EPROM to be programmed into the
		Programming Socket.

	  2.	Turn on the power and load the data to be copied into the EPROM
		into any portion of memory.  This may be RAM memory loaded from
		cassette (or by hand) or may be another EPROM which is going to
		be copied.

	  3.	Load the EPROM Programming Program from cassette (or by hand)
		into memory (locations 0000 to 00D8)

	  4.	Make sure the following application connector connections are
		in place:
		MICRO A-9 TO MP A-19;
		MICRO A-10 TO MP A-20;
		MICRO A-l1 TO MP A-21




 

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