development platform - a new sound card for the Spectrum DMA UltraSound Card.

<b>development platform</b> - a new sound card for the Spectrum
DMA UltraSound Card.

-----------------------------------------



            Ultrasound Card


          I. The head of the most important.

-----------------------------------------

               1. Introduction


    So what is this mysterious slovoDMA Ultrasound Card? How 
much any ridiculous myths and rumors enveloped this device, as 
no from all the previously created for SPECCY. And to this day 
are hotly debated in fido, and the most interesting thing is 
that the debate nick never before had seen this map

and have not heard her sound. And now,
when the major work on the creation of DMA
Ultrasound Card is already behind them, we decided to
write this article once and for all
do away with all these ridiculous myths.

    So, what exactly is DMA Ultrasound Card
primarily a sound card, built on the principle of direct memory 
access (Direct Memory Access), which has some

additional functions (see below).


      2. Technical characteristics.


    That all was clear to all cite
technical characteristics of the card with brief explanations.

Number of channels * bit: 4 * 8

Volume: 0-63 (6 bit)

Sampling rate: up to 3.5MGts (not kHz!)

   Most often, questions arise (spores) of

   sampling frequency, explain in detail:

   m / s i8237A (analog - KR1810VT37) work
   melts, according to the scheme, with a maximum frequency

   Sample 3.5MGts (7MHz some modifications
   tion for TURBO), to find such an application

   in the field of sound very difficult, because poppy
   The maximum sampling frequency. wav -

   48kHz. Therefore, in all characteristics,

   associated with sound, written 48kHz.

Serviced memory: up to 1MB

   (With service up to 16MB).

Max. sample size: up to 64KB

   (See page because the DMA not 16K as

   Z80, but in 64kb!). In general, the length of the sample

   not limited to, it just breaks up into

   multiple segments of 64kb.



     3. Additional features DMA


  1. DMA Ultrasound Card is the possibility of using an 
additional 2 Timer interrupt frequency from 30Hz to

1.7MGts. What is it? This is the case
programmer.


  2. Using a RAM card company gives
opportunity to use it as an accelerator for use with the 
blocks. Analogue of the team ldir Z80 processor running at 8 
cycles per byte at a frequency controller 3.5MGts, and for 4 
cycles at a frequency of 7MHz. Because pot size DMA - 64KB, 
16KB against Z80, you can make sending units

between pages.


  3. Program brake komputera. In test mode, the DMA controller 
issues only DMA request, and signals

sampling does not formirutsya. Therefore, the only visible 
effect - is slowing down kompyutera.V this mode, the controller 
generates maximum of 437,500 memory accesses per second, which 
leads to inhibition of companies to 50%. This mode allows you 
to fit frequency of appeals to set any speed

the computer.


  4. We can not say that the DMA
may play a HDD. wav-s 44kHz,
stereo with CD quality in realtime an unlimited length.


    What good is it? ", You ask, yes
Here's how: full or multicolor
Skoll full screen for 2 / 3 INT'a (at
7MHz - over 28,000 cycles). Programmatically
You can put any INT (top down).
Because sample is playing an interrupt,
you can play packed with sample
unpacking in real time.


    By the way, playing. Mod is over
interrupts, INT for 1000 cycles spent
Z80 (9000 peak).


        4.Programmnoe software.


   Software for this card has already been written fairly still 
not enough, this music. Editor Adapted by DMA-beloved Dig.

Studio,. Mod-,. Wav - players, FX-mixer,
utility installation speed kompaFreeSpeed, sound effects 
library - DSI, a whole bunch of fully voiced toys, etc., etc. 
Now is written and the other software.


    One of the biggest advantages of cards
is that any program written by
DMA, does not hang in the absence of such (in
Unlike the GS). Therefore, nothing prevents
you, for example, to play the game under the DMA,
just background music and effects will not.

    DMA Ultrasound Card unlike General Sound was designed not 
only to sound toy (see ZF # 7 - ~ Riff

Tracker ~), is a full, professional sound card.

    In subsequent articles I will try to
Programming Guide maps, methodology and build it with debug 
vsevomozhnymi tests and advice, with which the assembly map is 
reduced to the minimum cost time and effort.


    By the way, about the cost: DMA Ultrasound Card
cost bucks a 15-20 (GS costs $ 50!)
depending on the parts, import
Crayons are a factor of 1.5 higher. Well, the week
2-3 for assembly and commissioning.

Everyone who is interested or has kakielibo questions about 
this article or DMA Ultrasound Card please contact us at:



     85280, Ukraine, Donetsk region.

            Dzerzhinsk, pos. Kirov,

            ul.Yunosti 16/48

            Mihalchenkovu Dmitry

or by phone:

     (06247) 12.03.2006, Andrew with 16 to 21 ° ° ° °

-----------------------------------------
                        to be continued ...