Constructor - an original simple ADC circuit.

(C) Lezhenko Denis (LDE SOFT)

 SIMPLE ADC CIRCUIT
 ═══════════════════

   Here is a simple analog-to-digital circuit
digital converter, allowing digital
convert analog signals with 10/8 bit
quality. Despite the simplicity of the scheme,
The quality of the resulting digitizations is comparable to the quality
quality of digitizations obtained on a computer
max IBM/PC or AMIGA,and often superior
walks him.

   Well, what to do with these digital images? Du-
May, today there are a lot of stories -
no need to worry, let me just remind you briefly: this
production DIGITAL tools for
some famous music editors such as:
DIGITAL STUDIO, SAMPLER, INSTRUMENT, DMM
etc. And of course, the original design
development of their programs and megademics.


   Well, for those who understand the word ADC not
only as a toy capable of recording
music or voice into the computer, providing
there are enormous opportunities for experimentation
cops with analog signals. For example,
using a simple driver, the ADC can
turn into a digital oscilloscope, often
Tomer, voltmeter, multimeter, etc.

   ANow let's move on to the description of the connection
connection of the ADC to SPECTRUM. To connect it
I decided to use free ports
AY-3-8910 although you can use any
the ports you have (for example BBSS, with
this will even simplify software control
tion of the ADC). Now specifically according to the scheme: for
you will need to buy its assembly at Mitin-
on the radio market, the K111ZPV1A microcircuit and
one (1) resistor. ADC 15 is connected
wiring (12, 10, 16, 14 - power supply), 2-9
ADC to 21-14 AY-3-8910, 17 ADC to 7 AY, 18
ADC to 12 AY, 1 ADC to 11 AY, 11 ADC to 13
AY. Further on the diagram everything is clear.

   Now it's time to describe bit by bit
ports for working with ADC and writing your own
real driver. Port AY "A" is used for
receiving a byte from the ADC onto the data bus.  Port
"B" is designed to receive two junior
ADC bits (if desired, you can not use
use), receiving a ready signal from the ADC
ity, ADC reset/conversion.

   Learn more about port bitmaps
"B": bit 0 - blanking/conversion (0-ha-
conversion/1-conversion), bit 6 - ready
ADC capacity (0-READY) bit 1 - least significant bit
ADC (D0 ADC), bit 2 - first bit of the ADC
(D1). Such a strange bit layout is not
random, it’s easier to program the ADC. K
in addition, processing the two least significant digits
The ADC requires many Z-80 clock cycles, which
so not enough, that's why they were bred from me
to a separate port and you decide for yourself whether to useuse them or not. I personally have them
reserved and I'm quite happy with 8
bit quality of digitizations.

   ADC control features: pin 15
is intended for selecting the conversion mode
vaniya. Let me explain: if there are logical logic at pin 15
0, then the ADC operates in unipolar mode
meh. To switch the ADC to a bipolar re-
Press pin 15 should be free. Manager
Signals: pin 11 ADC: damping
signal generation/conversion.   Managed
bit 0 of port "B" AY. Has the following meanings:
Values: 1-quenching, 0-conversion.  After
receiving the ADC conversion signal starting
knows how to convert an analog signal into
digital form using the sequential method
approaching. Therefore, the digital code at the output
de ADC appears with a slight delay:
about 3Ox or about 11 cycles of a Z-80.
This circumstance must be taken into account, or
poll the ADC using the readiness signal (17
ADC output, or 6 bits of port "B" AY).  When
logical 0 on this pin of the ADC is ready and
You can remove bytes to the data bus.



   After the ADC outputs the "go-
Comrade", you need to read the byte in RAM, after
go reset the ADC (see above) and send a signal
transformations. Otherwise, the ADC output will be
sit the old byte and you will fill the RAM all-
with one digital count.

   Yes, I forgot to remind you that for ra-
ADC bots need -15 (or, at worst,
Nets, -12 ) volts, I also remind you that in
blockpower supply from IBM such voltages
yes.

   Technical data of this ADC: max.
Low conversion frequency - 44000 Hz.
With the appropriate driver, the conversion time
formation of 1 byte: at signal frequency 50
Hz no more than 30 µs (10/11 Z-80 cycles).
Supply voltage: +5V, ChmA; -15V, 1SmA.
Input voltage in modes: unipolar
- 0...11V, bipolar: from -5.5V to +5.5V.

K 7n/ AY ────────────────────┐
                             │ █▀█ █ █ █▀█
                 K111ZPV1A │ █▀█ █▄█▄ █ █
                ┌─────────┐ │ ▀
K 12н/AY ───18──┤D0│ │ __│17│
K 11н/AY ───1-──┤D1│ │ DR├──┘ ┌────┬─────< Login
K 21н/AY ───2───┤D2│ │>0<├──15─┬───┐ │ │ R1-4.7k
K 20н/AY ───3-──┤D3│ │OVA├──14─┘ ─┴─ │ █
K 19н/AY ───4-──┤D4│ │ AI├──13─────────┘ │
K 18н/AY ───5-──┤D5│ │-U2├──12──────────────┴─────< -15v
K 17н/AY ───6-──┤D6│ │+U2├──10────────────────────< + 5v
K 16н/AY ───7-──┤D7│ │OVD├──16──┬─────────────────< General
K 15н/AY ───8-──┤D8│ │___│ ─┴─
K 14n/AY ───9-──┤D9│ │G/P├──11─┐
                └─────────┘ │ (c) L.D.E. SOFT 1995
                                │
K 13н/AY ───────────────────────┘

   Well, that's all for a short description of the sub-
switching and programming the ADC.  If you
who has questions about this, then
contact me by phone (095)
400-0436or come to me at Mitin-
Russian radio market (place X-5), or write
at the address: Moscow, 127572 Novgorod St.
Skaya house 27, apt. 55 Lezhenko to Denis (LDE
SOFT).

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