Iron - 8-bit ADC for COVOX, brightness signal generator for a monitor.

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║ SECTION: IRON ║
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 8-bit ADC for COVOX

Characteristics:

 Conversion frequency - at least 50 kHz.
 Bit capacity - 8 expandable
until 10.
 Small number of parts and their non-scarcity.

 ADCis designed for connection to port "B"
music coprocessor, but maybe
connected to any other SPECCY port,
or (with the addition of a decryption scheme) non-
directly to the data bus.







































УСТРОЙСТВО И НАЛАДКА. АЦП состоит из реги-
стра последовательных приближений 155 ИР17
ЦАП`а  572 ПА1,comparator (comparator
analog signals)  554 SAZ and register
storing the result 1533(555) IR23. After
arrival of a low-level impulse on the 14th
register output ИР17 its outputs Q0...Q11
are set to "1". At the output of the DAC at
This generates a voltage of approximately 5V.
Next, one by one, starting from the oldest
row, the outputs of IR17 are set to “0”.
If the signal at the output of the comparator
does not change, then it returns to the discharge
"1". Thus, for a minimum quantity
cycles, a binary code is selected, corresponding
corresponding to the signal level at input 3 compa-
ratora. The cycle ends with the recording of the received
of this number inIR23.
 When setting up, remember that the inputs of the microcircuit
we 572 PA1 have a CMOS structure and require
appropriate precautions. Re-
a 240 Ohm resistor is needed to reduce the maximum
voltage at the output of the DAC chip
up to +5V, it can be replaced by two in series
specifically turned on diode KDS21 (KDS22).
A 200 kOhm resistor is used for adjustment
zero. Without240 pf capacitor may not be sufficient
sing to register any digits
transformations. input condenser capacity -
The comparator torus can be increased by
at your discretion.
  The H2 frequency is 0.875 MHz - in "PENTAGO-
NOT 128 "it can be found on the 2nd pin IE7
D3. The circuit is designed for use PA1 s
letter A. ForPA1 withanother clock letter
the frequency may have to be reduced by half
times.
  To test the device write
program that reads and prints a number from
port ADC. Rotating the trim knob
resistor, smoothly change the voltage to
+I input from 0 to +5V. Moreover, the number in
the mouth must consistently accept everything
values from 255 to 0. If this is not the case, then
select resistor values more accurately
and a capacitor (see above). Allowed
excitation ADC in static mode in
narrow interval between values 127 and 128
To check the dynamic mode, apply
signal INPUT  - its amplitude on the 3rdconclusion
554 SAZ must be within 0...5V. EU-
if this is not the case, then pass the signal through
resistor or use an amplifier. Vra-
By using the variable resistor motor, you can achieve
ensure optimal (auditory) digital quality
roving. Don't forget to install a locking
private capacitors between power buses.

 IMPROVEMENTS. Bit capacity  ADC can be increased
Power up to 10 if you connect outputs 6 and 7
Р17 with inputs 13 and 12, respectively PA1
Signal to pin 14 IR17 and then the inverter
should be taken from the 5th pin IR17.
The quality of digitization can be improved if
use sample-and-hold device
analog information for the time of conversion
Vania (UVH). Analog storage device
swarm can be assembled on discrete elements -
ntakh or use chip 1100 SK2
The diagram of such a device can be found in
reference literature.

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Brightness signal generator for monitor

    Hello, dear readerFANTOM`a!
I, Dr. Lion/RSM,I offer you another
finishing your coffin, proudly called
SPECCY (ALIVE 4EVER).Have you ever
ever connect such "special" to the ZX
new" color monitors, like "KODIS-M", "ELE
KTPOH" and the like? Their feature is
lies in the fact that their inputs need to be
give digital signals from a computer.  Other
feature is the presence of a separate
brightness input called "I".  Level on
this input determines one of two brightness
these are the main eight colors. That is, if on
input "I" log. 0 then colors with normal brightness
bone, if log.1 then colors with increased brightness
bones. To get on the monitor screen
all 16 colors just need to be submitted to the input
"I" brightness signal from the computer. You can lay it down
to find according to the diagram - it comes out of the multi-
plexer and through three diodes it is supplied to RGB
colors. In general, we connected the brightness to the mo-
nitor and what do we see as a result?  Flowers
looks like it's 16 now, what are these gray ones?
anoint on the screen? I immediately remember
one of the features of the ZX is that the black color is not
shouldhave gradations of brightness. Pressing RESET
and BREAK we see in the color table that
black color has a brighter shade -
tion - gray color. This gray color
smudges everything on the screen. What needs to be done, yeah
how to get rid of this effect?  Need co-
take the driver circuit below
brightness signal for a color monitor:
















VPENTAGON`e mikruhuK555LECHconveniently attack
on top of D72 (according to the scheme where A1-A16). When-
pins 3,7,14 LECH to the same name are soldered
pins D72.  The remaining legs bend back and
soldered in accordancewith a diagram. Si-
DR and DG signals are taken from the same D72, from its
legs 6 and 8 respectively.  Brightness signal
BR can be taken from the 9th leg of D47 or from
diodes VD13-VD15.  Signal I is supplied
to the monitor input of the same name.  Revision in
does not require adjustment, so everything should
work the first time. Good luck to you!!!
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