                    ENGINEERING CHANGE NOTICE

ECN Number:__________10_______________________

Product:____________MPZ80_____________________

Part Number(s):_____125-0015-00_______________

Current Board Revision Number:______3_________

New Board Revision Number:__________4_________


Purpose  of Change:_1)_ADD_EXTRA_MEGABYTE_ADRESS_SPACE_TO_BOARD_

2)_ELIMINATE_WIRE_JUMPERS_ON_BOARD_FROM_PREVIOUS_ECNS.__________

3)_CORRECT_A_PROBLEM_WITH_I/O_TRAP_LOGIC_UNDER_MOS._____________

Modifications (attach additional sheets if needed): ____________

_1)_TO_ADD_AN_EXTRA_MEGABYTE_OF_SPACE,_THE_UNUSED_BIT_3_OF_THE___

MEMORY_PROTECTION_RAM_WILL_BE_CONNECTED_THROUGH_A_BUFFER_TO_S-100

ADDRESS_LINE_A20.__THUS_THE_UPPER_BIT_OF_THE_PROTECTION_RAM_WILL_

NOW_TOGGLE_WHICH_OF_THE_FIRST_TWO_MEGABYTES_WILL_BE_ACCESSED.____

NOTE_SOFTWARE_DOES_NOT_YET_SUPPORT_THIS_BUT_BOARD_WILL_STILL_BE__


APPROVED:      Engineering:______________________Date__/__/__

               Production:_______________________Date__/__/__

               Quality Assurance_________________Date__/__/__

               Customer Service__________________Date__/__/__

               Purchasing________________________Date__/__/__

               Marketing_________________________Date__/__/__


EFFECTIVITY:   [ ]  Immediate - notify current production

               [ ]  Notify users and update stock

               [X]  Phase in as stock is depleted


Submitted by:__BOB_GROPPO_____________________________on 4/9/84_
 
Page_1_of_5_                                 Schematics?___YES___



ECN #:______10_________                               DATE: _4/9/84_______

PRODUCT: __MPZ80________                              PAGE: _2_ OF _4_



MODIFICATIONS:     BACKWARDS COMPATIBLE WITH EXISITNG SOFTWARE. 
(cont.)            (SEE FIGURE 1 FOR SCHEMATIC CHANGE DETAILS.)

                2) THIS CHANGE IS TO INTERGRATE ECNS 4, 5, 7, AND 9  
                   INTO THE ARTWORK IN ORDER TO REMOVE ALL JUMPERS.

                3) THIS CHANGE WILL ALLOW MOS USERS TO PERFORM DIRECT
                   I/O IN MULTI USER MODE. CURRENT DESIGN FLAW WILL NOT
                   ALLOW DIRECT I/O UNDER MICRONIX.  (SEE FIGURE 2 FOR
                   SCHEMATIC CHANGE DETAILS.) 

                4)  NOTE:  There are  no component changes. These 
                           changes   affect  only  the  PC  board 
                           artwork.   Revision 3 boards cannot be 
                           retrofitted  and  are  therefore  made 
                           obsolete by this ECN.   CHANGE IPMS AS 
                           DESIGNATED BY ATTATCHED FORM.   Change  
                           BOM as follows:
     



                        CHANGE BOM FROM:


ITEM    E  COMPONENT                                      EXTENDED
 NO.    R  PART NUMBER      PART DESCRIPTION              QTY. PER

 007       125-0015-00      PCB CPU MPZ80                     1



                         CHANGE BOM TO:


ITEM    E  COMPONENT                                      EXTENDED
 NO.    R  PART NUMBER      PART DESCRIPTION              QTY. PER

007        125-0015-01      PCB CPU MPZ80 REV 4              1 
     


CHANGE IPMS AS DESIGNATED BY ATTATCHED FORM 