Virtual World #14 27 декабря 1997

Доработки     Железо

Simm on ZX! - On connecting 30-pin Simm to ZX.

          SIMM on the ZX!


(C) MAXWELL / JS


  Recently I brought a friend with Fido
nozhesleduyuschy text and I thought
'Rather than whether to put it to me here'? Not all have seychas
Output in FidoNet, as well shemka pretty interesting, although 
we have it not yet experienced; yet can be

someone of the readers will be interested to understand it. And 
yet. When you convert the text has been lost 'cap' the author's 
name this scheme. Bring pre-

We apologize to the author and readers.
________________________________


  More than once the question arises
connected to the SIMM ZX-Spectrum.
Throw all the information about
30-pin SIMM.


     30-pins SIMM (SIPP)

 N pin name N pin name

 1 +5 v 16 D4
 2 CAS 17 MA8
 3 D0 18 MA9
 April 19 MA10 MA0
 5 MA1 20 D5
 6 D1 21 WE
 7 MA2 22 GND
 8 MA3 23 D6
 9 GND 24 NC
 10 D2 25 D7
 11 MA4 26 D8-out
 1912 MA5 1927 RAS
 13 D3 28 CAS-pr
 MA6 14 29 D8-in
 15 MA7 30 +5 ​​v



  All signals MAi, RAS, CAS, WE
the same as that fed to the RU5 or
RU7. Inputs and outputs data
SIMM combined, so if
PC DI and DO Chipset
RU5 (7) are joined together, the buffer is not needed. If they 
are separate, then when you install SIMM need to install an 
additional buffer between the data bus processor and data bus 
SIMM. 



      In the scheme of the computer.


                       from DI Z80

         RU5 (7)


       DI DO to clipboard


       WE


                       signal

                       record



        Connecting SIMM


        555AP5


    oOE


     .. ..

     DI DO


                   from DI Z80


       SIMM


            Di on the clipboard

     .. ..



     WE


                    signal

                     record


  CAS-pr connected to +5 v through
1k. NC, D8-out, D8-in is not
connect anywhere. MA0 .. MA10 -
multiplexed address of the URLs RU5 (7).


  256k SIMM - not connected
MA9, MA10


  1Mb SIMM - not connected
MA10


  4Mb SIMM - connected to all the addresses


  When you connect the SIMM must be remembered that memory must 
be reclaimed, ie, every few milliseconds to select data from 
all columns. This can be achieved by throwing out the processor 
addresses and The video for multiplexers

RAM addresses.


       Regards, Ivan


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