KrNews #12 01 апреля 2000

Железо

Mosaic - signal in the scheme Spectrum IORQGE.

   So, sir, now get down to Optron,
number 33'y. While all right, well, it will not swear ...

... Deleting 12optron.txt ...


   No, it is necessary to restore justice,
Toko no accident.

   So, my hardware soul, was brutally
offended arrivals on one of the cornerstones spekovskoy 
architecture, and It is IORQGE.


   And it was so. Went to 13'oe Polesie article about this very 
signal. Well, I have no claim to it in practice,

except for the resistor, pull-up input
555LL1 to land in the scheme of the shaper
IORQGE (incidentally, in his denomination ZXHard'0
too bad). He should be somewhere in the
1 k (555.1533), and better 510-750 ohms
(155.531). This is due to the fact that when
TTL-input is logic 0, it follows from the entrance into the 
source of significant signal current I (0) input (see 
references): 



               +5 V


      TTL



     I (0) Rin

       e / / k

       <
r (i)

              ...



   This current sozdet decent drop
voltage r (i), which can be
received a logic 1 ...

   I also note that when pulling up
TTL inputs to +5 v resistors can be
10-20 ohms, as input transistor in this case is closed and I 
(1) input has the order of hundreds of microamps or less.



   Well, in general in Optocouplers have called for
Universal-decoding severely for what they
an enormous factor. I've already written in
ZXHard'0, how it is done to
conflict was not. And if you are connecting
Several devaysov need to hang Chains, you behold in the scheme 
of Kay look-out there for each slot has its own pair 
IORQ-IORQGE. 



  high priority low

      <


    device-1 device-2


  iorq iorqge iorq iorqge



                          out
iorq iorq
z80 1 ​​January

                         in the complex


    k68 k68

                1533LL1



   And yet, no problem. Normally connect the device in such a 
system: device with more rigid decryption must be included in a 
priority slot (on Kaya - Far more (physically) from the Z80),

not to be blocked addresses "rougher address. In practice it 
might be easier to just poperetykat Soup in the slots while 
they are not work. 



   And as promised shemki Flash-color - broken off, no one is 
yet nafig not necessary. So I still meditate about

All these graphics pribabahah. Maybe
and it is not necessary components to distort ...