City #35 04 декабря 1999

Железо

Iron - Three schemes matching Modem Spectrum'om.

   ************ ********* PLANET SHELEZYAKA


(C) Darth Vader / Triumph


    Matching circuits Modem Spectrum'om

          (Reproduced with modifications)

              Copyright G. Shepelev

from the computer contacts the slot modem:

DATA 0-7 A9-A2 DATA 0-7


   A15 555LL1

             1

                     1 A22, A23 A9, A8

   A14 O

                                A24, A25 A7, A6
 A13, A12 10k

                   +5 V  IORD (B14)
 RD 1> IOWR (B13)

      LL1 November 13

     March 1
 A4 1 o

     2 LL1
/ IORQ

              1
 / WR o


                   K555TM2


           +5 V 1 R Q 5


               3 C
 A11 2 D

/ RESET o 4 S



           1 RESDRW (B2)


     K555LN1


                   1 / NMI
IRQ4 (B24) 1



                   MODEM

       A8 A0 (A31)
By A9 A1 (A30)
On the A10 A2 (A29)
M
N D0-D7 D0-D7 (A9) - (A2)


on the +5 v 10K A3-A10 (A28) - (A21)

        GND AEN (A11)


  Used K555LL1, K555TM2 and K55LN1.

  Do not forget to bring power to the modem and Wrotham
to set the jumpers on the modem and COM1 IORQ4.


  -5v - B5-12v-B7

  +5 V - B3, B29 +12 v-B9

  GND - B1, B10, B31

-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Matching circuits Modem Spectrum'om
 (A modified version of the scheme M. Kondrateva)


               LL1
 __ 12> IORD (B14)
 RD 1> IOWR (B13)

       LL1 November 13

     March 1 __
 A4 1 o __ o> IORQ4 (B24)
____ 2 LL1 LA3
IORQ o 4 6 4

               TM2 1 o '6
 __ 5 1 5 o
 WR +5 B> oR 6

                         2 o
A11 D

                         March 1 LP8

                          / C o o 3
___ 4 5 2
RES o oS


                                    5 LP8

          LA3 +5 V> o o 6

        4 ___ 4

       o '6 ___ o o

        5 o LP8


                                   12

                                         11
 __ 13
 M1 o

 D1
___
INT

                                       > RESET (B2)

+5 B>> to vyv.14 chips LL1, LA3, TM2, LP8


        > To vyv.7 chips LL1, LA3, TM2, LP8



  In parentheses are pin numbers on the modem board. On the 
left the signals connected to the Speccy, and to the right to 
the modem. 

  Products: 555LL1, 555LA3, 555TM2, 555LP8.

  Resistors: 1k


            Refinement scheme Spectrum

            ~~~~~~~~~~~~~~~~~~~~~~~~~~


                   Z80

      cut

                ___

           x INT

          ___

         |___|

        / 560

    add

                   ___

                  > INT


            Wiring diagram for Spectrum'u

            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  Modem System

   port
 _____ __________
| A 8 |----> | a31 | A 0 |
| A 9 |----> | a30 | A 1 |
| A10 |----> | a29 | A 2 |
| D 0 |----> | a9 | D 0 |
| D 1 |----> | a8 | D 1 |
| D 2 |----> | a7 | D 2 |
| D 3 |----> | a6 | D 3 |
| D 4 |----> | a5 | D 4 |
| D 5 |----> | a4 | D 5 |
| D 6 |----> | a3 | D 6 |
| D 7 |----> | a2 | D 7 |
| | | A28 | A 3 | -
| | | A27 | A 4 | AT
| | | A26 | A 5 | +5 v
| | | A25 | A 6 | a
| | | A24 | A 7 | 3-10k
| | | A23 | A 8 |
| | | A22 | A 9 | -
| | | A21 | A10 | - on the ground
| | | A11 | AEN | - on the ground
| | | B9 | +12 v | to the corresponding IP | | | b7 |-12v |> 
source of stress | | | B |-5v | / modem if required

| GND |----> | b1 | GND |
| GND |----> | b31 | GND |
| +5 V |----> | b3 | +5 v |
| RESET | - by - | b2 | RESET |
| RD | - | b13 | IOWR |
| A4 | - n | b14 | IORD |
| IORQ | - L | b24 | IORQ4 |
| WR | - a | | |
| A11 | - T | | |
| INT | - y | | |
| _D1__ | - |__________|
 signal signal


  Unlike the scheme of the prototype in the process of issuing 
interrupts to the computer. Because possible alter ROM we 
nebylo, we decided to use the normal INT, rather than NMI. 
Interrupt processing is performed in the mode of IM2. It should 
be noted that the issue interrupt to the computer from the 
modem is accompanied by change the interrupt vector that is 
easily tracked in the mode of IM2. Thus retained the ability to 
work with interrupts coming from the computer. 

  No other differences and programs that do not use the same 
interrupt from the modem will work on any option scheme.