Atari stereo 1_2.

By Administrator at September 14, 2015 20:00
Filed Under: Atari

 

ATARI STEREO


Malé Atárko a stereo zvuk ? Áno je to možné.

 

Prvú verziu stereo  zvuku pre malé Atari vymyslel Chuck Steinmann a malo prezývku "Gumby". Ako to už býva, rok vzniku nepatrí medzi najmladšie, jedná sa o rok 1989 ... Odvtedy sa ale niektoré veci zmenili, niečo sa podarilo vylepšiť a tak teraz máme k dispozícii verziu stereo zvuku, ktorý je naozaj dobrý a je len škoda že to tak nebolo už priamo v základe návrhu počítača. Dnes sa ale budem venovať iba tej prvej verzii - Gumby. Jedná sa o hardvérový zásah do počítača a teda potrebujete na konci pripojiť stero zosilňovač. Samozrejme nie všetko je urobené na na stereo, takže treba zachovať kľud a pitný režim ... Tu si o tom môžete prečítať zopár riadkov. Bez bitky sa priznám že osobne neznášam tieto tzv. ASCII návody, kde je niekoľko strán textu namiesto schémy. Ak by bola tá schéma bolo by to jasné ako facka. Lenže vtedy internet ešte nebol a tak šírenie obrázkov nebolo také jednoduché, tobôž ak neboli ustálené a hlavne rozšírené obrázkové formáty - a ich prehliadače. Iný podklad nie je v súčasnosti k dispozícii o tejto verzii a tak mi nezostáva nič iné ako zobrať do milosti aj takýto "návod". Boh s Vami ...

 

Ako sa dostať k programovému vybaveniu ? Zadajte text, ktorý je na prvom obrázku ... Gumby stereo player.


            

ATARI 8-BIT IN STEREO 8-BIT IN STEREO ---------------------
A great gadget is the stereo upgrade from Chuck Steinman. The
following text describes how to build a second POKEY chip inside your
Atari 8-bitter. I've been told that POKEY chips aren't very expensive in
the USA so I think I'll try to get some. Wouldn't it be great to have four
channels stereo sound? Software? Well, first take a look at side two of
this disk and unpack the GUMBY file. I hope some hardware freaks will
soon develop an 'easy to install' version of this useful gadget so
everybody can have it without being familiar with electronics. Then it
would also be more fun to write some software for it. ------------------------------
POKEY STEREO UPGRADE by C. Steinman (GEnie User: DataQue.1) Information file for adding stereo to an Atari 8-bit compute using two
pokey chips.
Note: Installation of this modification will void any warrenty you may
have on your computer. Chuck Steinman, DataQue Software, or GEnie
telecommunication service cannot be held responsible for the installation
of this upgrade or any incidental orconcequential damage to any
equipment or persons using this upgrade or any variation of it. In other
words.... you are on your own. This is upgrade version #1. It will only provide stereo output for software
written specifically for this upgrade.
It will not software written specifically for this upgrade.
It will not produce stereo output for existing software.
Also, the keyclick will NOT be fed into the stereo outputs, as it does not
originate from POKEY. Parts Needed ------------ 1) Second Atari POKEY Chip a) BEST CO12294 $5.00 b) B&C ComputerVisions C2294 $3.50 2) 74LS14/74HCT14 Inverter a) BEST (74LS14) CO16541 $0.30 b) Jameco (74HCT14) 74HCT14 $0.29 3) 1000 Ohm, 1/4 Watt Metal Film 2-5% Tolerance a) Jameco (10 lot) R1.0K $0.50 for 10 b) Radio Shack (2 lot) Dont know P# or $ 4) Two RCA style phono jacks a) Radio Shack, Jameco or other electronics outlet 5) Two 0.01 (or close) 16V (or more) bypass capacitors. Jameco DC.01, $0.10 each 6) Two short (6-12" each) sections of shielded audio cable. 7) A standard dual RCA to RCA patch cable. 8) Optionally two 50k single turn trimmer pots. Jameco 63P50K $0.89 each
Hardware -------- 1) Inverter Information a) Bend up all pins of the inverter except for pins 7 and 14. b) Cut off the narrow part of the pins which were bent up. c) Install the inverter over top of the existing 74LS14 (or another 74LS
 part if more convenient on the motherboard. Make sure that the new
chip has its locator notch/dot on the same end as the chip below it. d) Solder pins 7 and 14 of the inverter to the same pins of the lower IC. e) Run a small wire (wire wrap type works best) from pin-1 of the inverter
to pin-13 of the CPU. The CPU is part number CO14806 on the XL/XE
series. f) On the old POKEY there is a 3k pullup resistor connected between pin
31 and Vcc. You will need to unsolder this resistor and remove it. g) Run a small wire from pin-2 of the inverter to pin-3 of the inverter,
and then on to POKEY pin-31. Note, you can use the pad where
the resistor was just removed. Be sure to get the correct one.
2) POKEY Information a) Bend up all pins on the new POKEY which are marked with a minus
 on the diagram. This includes POKEY pins: 8, 9, 10, 11, 12, 13, 14,
 15, 16, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 3, 14, 15, 16, 18,
 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 and 29. b) Cut off the narrow part of each pin bent up. c) Tin each lead which was NOT bent up. This includes pins 1, 2, 3, 4,
5, 6, 7, 17, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 and 40. These
pins are marked in the diagram as *,>>, or <<. d) Now, bend up the pins indicated by the >> and << symbols. Do NOT
cut these pins short. e) Place the new POKEY on top of the old POKEY in a piggy-back style. f) Solder the unbent pins of the new POKEY to the old POKEY. If your
original POKEY was in a socket, then it is easier to connect the two
if it is removed. Make sure no excess solder flows down the pins to
the narrow part of the OLD POKEY.
Reinsert both POKEYs into the original socket.
g) Solder the 1k resistor from pin 37 to Vcc. The most convenient
location to pick up Vcc is where the 3k resistor was removed earlier. h) Solder a wire from pin-31 of the new POKEY to pin-4 of the inverter. i) Mount the two RCA jacks on the rear of the case, preferably in an
area close to the POKEYs
 j) Solder a bypass capacitor to each of the center conductors of the
RCA jacks.
k)
*With the trim-pot knob facing you, pin 1 should be to the left side.
Solder a wire from this pin on each trimmer, to a ground trace on
the motherboard. l)
* Connect the free end of the bypass capacitor to the center pin of
the trimmer (one capacitor to each trimmer).
m)
*Connect the shields of the audio cables to the provided solder
plugs on each RCA connector, and the center conductor of the
free terminal of each trimmer. n) Connect the center conductor of the free end of the audio cable
which is connected to the left RCA jack/trimmer/cap to pin-37 of
the OLD POKEY.
p) Connect the center conductor of the free end of the audio cable
which is connected to the right RCA jack/trimmer/cap to pin-37
of the NEW POKEY.
q) The shield of the audio cable on the POKEY end, should be cut
and taped (or heat shrinked) so that it does not touch anything. r) Run a 18-20 AWG wire from the ground lug of the RCA jacks to
the wide ground area on the motherboard. This normally makes
contact with the shield box that covers the motherboard. s) You will now be able to connect the two RCA cables to an AUX
(or Tape) level input of a stereo or boom box.
 t)
*I would suggest centering the trimmers in their travel, and
adjusting them as needed to get the best clarity. You may want
to glue the trimmers to the back of the cabinet to keep them from
moving around.
* NOTE: On my system the POKEY outputs worked fine without the
trimmers. So I just connected the bypass capacitor on each RCA
jack to the apropriate audio cable center conductor. This was
driving an AUX 350mV input of a Pioneer SPEC-1 preamplifier.

 

C) POKEY Registers:
          
I will only elaborate on registers used to produce sound in the stereo
upgrade. All registers which were in the original POKEY will appear in
the second POKEY 16 bytes higher in memory.
The extra UART, key scanner, and pot scanner could be used for all
kinds of neat projects. Addr. Name R/W Function ------ ------ --- -------- $D200 AUDF1 W Audio Channel #1 Frequency (Divide F/n) $D201 AUDC1 W Audio Channel #1 Control (Vol/Distort) $D202 AUDF2 W Audio Channel #2 Frequency (Divide F/n)

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Volám sa Igor Gramblička, bydlisko: Bratislava, Slovakia. Môj nick: Igi. Blog je o mojich záujmoch - som už na dôchodku, predtým som pracoval ako IT špecialista na počítačové siete a redakčné systémy vo viacerých denníkoch - až som pred rokmi nakoniec zakotvil v jednom denníku kde som to potiahol až do konca mojej profesnej kariéry.