Technical description of the PHOENIX melody module KMM6221/03 from RFT.
=======================================================================

In spring 1997(?) in a box of garbage of my neighbour in the German city Bux-
tehude I found a white plastic thing with a loudspeaker,which apparently once
was the rear half of an electronic doorchime.The electronics looks like part-
ly handmade;there is an industrially produced small PCB module in it which
is connected to some simple handmade circuitry with a large,old rotary switch
(like from a tube oscilloscope) and a 100Ohm potentiometer.

At home I tried to connect the thing to batteries;when a contact is pulled to
+,the thing plays 2 voiced squarewave melodies.The potentiometer is in series
with the 16Ohm speaker to adjust the volume.By turning the rotary switch,6
different melodies,Westminster and some gong effects can be selected.After I
had tested it,I put the thing away into a closed box with some of the other 
squarewave music things I have collected.

The doorchime rested there for a long time without that I cared much about it.
When I recently looked again at the thing,I got aware of that on a small,
white,rectangular,worn off paper sticker on the module PCB the words "RFT - 
PLEIADES" are printed(with typewriter?) and the word "PLEIADES" has been
crossed out and overwritten with pencil by a smeared word that looks like 
"Phönix".I guess I have looked at this sticker already several times,but I 
didn't realize its meaning yet.
Now I would love to know if this indeed may have been the melody module of a
"Phoenix" arcade PCB.The melodies are all different from the MAME version and
they are also not the "Greensleeves" version.


The melody module has a red plastic connector with 18 pins.On its small PCB
are 3 ceramic capacitors,7 resistors,a cylindric metal transistor,a 2 pin con-
nector for the speaker and an 18 pin IC.The IC has a brownish orange ceramic 
body,brass pins and in the center a silver metal top(aluminum??) with black,
a little smeared printing on it.Th IC is not soldered in,but sits in a grey
plastic socket.The PCB is dark brown,single sided and has quite broad traces
those are coated with solder.

On the IC stands:
.------------------.
| |1984 RFT 01 04| |
| |              | |
|°|  KMM6221/03  | |
'--==============--'

(The 2nd "M" is halways scratched,though this one is a guess.)

On the PCB itself stands(in letters etched out of the copper) "MUSIKA".The
wires of the rotary switch are soldered by many glass diodes(larger than
usual ones) to the connector's back side of the module.Outside the module a
rectifier circuit formed by 4(quite big) glass diodes and an electrolytic cap
(80MF +35V,4cm long,axial) are glued to the doorchime case(but there is no 
mains transformer included).The thing works well with 5V AC or DC;the sound
from the speaker gets already audible with 2V,but extremely quiet and distor-
ted.


The doorchime plays the follwing melodies:

Switch positions:

1  4 Melodies (one per button press|1=DDR hymn?,4="Barcarole")
2  "Oh Tannenbaum" (a German xmess carol)
3  "Litle Town of Betlehem"
4  "Barcarole" (a very nice squarewave tune)
5  4 tone chime
6  Westminster? (a clock chime)
7  2nd 4 tone chime 
8  dong (1x)
9  a kind of ringing telephone bell sound
10 (empty) 

I have asked my neighbour Schmidt about the origin of the strange module.He
told me that in former times he lived in Zwickau in the "DDR"(the soviet occu-
pied zone of eastern Germany) and that about 1988 he got the doorchime from a
guy of the name Pirl by swapping with him a kitchen clock for it.As a hobby
and additional income source Mr.Pirl repaired radios and TV sets for other
people and he had good connections to get electronic spare parts,which in the
DDR was a difficult task.He had built the doorchime of scrapped electronic
parts he got from other people.


I have tried to examine the working of the IC by carefully drawing pins to GND
or +5V using an 1kOhm Resistor and analyzing the wireing of the selector 
switch.Though I found the following out.(All mentioned mode names are by me;I
have no data sheet,though I don't know how the manufacturer RFT calls them.I
hope I didn't confuse anything;the mess of black cables from the rotary switch
where I connected the aligator clips is anything but well overviewable.)


KMM6221/03 - Theory of operation
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Most inputs are low-active and all treat open input lines as high.Most of the
module pins are connected with the corresponding pins of the IC.Pin 10,11,12
of the module are not connected.(The IC has a capacitor and a 150kOhm resistor
there which sets the clock speed.) Also pin 13,14 of the IC are not connected
and seem to do nothing.Pin 5 and 6 output each one of the 2 squarewave voices
(stereo ;-) ) and they are also internally connected by 2 resistors to the
speaker output transistor.Pin 18 is GND,pin 1 is positive supply voltage.On
the PCB there is a 330Ohm protective resistor between pin 1 of the module and
pin 1 of the IC.


Pin 7 and 8 combination selects 4 sound banks:

  00b = "chime" mode
  01b = "clock chime" mode
  10b = "xmas melodies"(?)
  11b = "other melodies"

  The melodies in each bank are selected with pin 9 and 16.


Pin 15 switches between 2 melody selection modes:


* when pin 15 is pulled low: (direct selection mode)

  Pin 9 and 16 directly select by their bit combination one of maximum 3 melo-
  dies/sounds from each bank.A high on pin 17 starts the selected melody and
  plays it once;when pin 17 is already high(or open) during selection,the se-
  lected melody is started immediately.Selecting "silence" stops any melody/
  sound.Keeping pin 17 high after a melody is finished doesn't play another
  one.Further signals at pin 17 while a melody is still playing have no effect
  (like desired for a doorbell button).

  (In the doorchime an external 100kOhm pulldown resistor has been soldered
  to the module to hold pin 17 down until the doorbell button contact pulls
  it high.)


* when pin 15 hi/open: (sequence mode)

  In this mode all melodies of a selected bank can be played in sequence with-
  out the need of changing the settings of pin 9 and 16.After the last melody
  of a bank has been played,the 1st is played again.

  The bit combinations of pin 9 and 16 do the following:

  00b = resets selected bank to its 1st melody(and plays it when pin 17=hi).
  01b = plays the next melody in sequence from that bank(as soon pin 17=hi).
  10b = similar like 10b (I call this "music box mode".)
  11b = silence (Immediately stops any running melody.)

  Setting pin 17 high(or open) plays the next melody once when pin 9,16 are
  set to 01b,or plays always only the 1st melody when they are at 00b.

  In mode 00b and 01b keeping pin 17 high after the melody is finished doesn't
  play another one.Further signals at pin 17 while a melody is still playing
  have no effect(like desired for a doorbell button).

  In mode 10b keeping pin 17 high when a melody is finishing starts the next
  one,though all melodies of the bank play in a loop when pin 17 is kept high.
  A rising signal edge at pin 17 while a melody is still playing skips the
  running melody and starts the next one of the bank.

  (In the "clock chime" mode the sequence mode behaves differently.)

  Independant from pin 15,any signal changes on pin 9 and 16 seem to take ef-
  fect only when they are at least ca.0.2s long.


Decription of the 4 sound banks:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
(The decimal numbers before the sound/melody names are the bit values of pin
9 and pin 16.The binary number "(**b)" here are the combination of pin 7 and
8.)

* direct selection mode (pin 15=lo)

    "chime" mode (00b):

      0=dong (1x)
      1=4tone chime
      2=a kind of ringing telephone bell sound(rings as long pin 17=hi).
      3=silence

    "clock chime" mode (01b):

      0=Westminster?
      1=dong (same as 0 in "chime" mode)
      2=2nd 4tone chime 
      3=silence

    "xmas melodies" mode (10b)

      0="Oh Tannenbaum" ("Oh Christmas Tree",a German xmess carol)
      1="Little Town of Betlehem"
      2="Barcarole" (no christmas carol)
      3=silence

    "non-xmas melodies" mode (11b or both open)

      0=melody 1 (DDR hymn?)
      1=melody 2
      2=melody 3
      3=silence


* sequence mode (active when pin 15 hi or open)

    "chime" mode (00b):

      (behaves like in direct selection mode.)

    "clock chime" mode (01b):

      0=reset to 12 o'clock
      1 plays 1 to 12 times "dong"
      2 plays Westminster(?),then 1 to 12 times "dong",then the "2nd 4 tone
        chime"
      3=silence

      Like a clock does,each trigger of pin 17 lets sound one clock strike
      more than the previous one;after 12 strikes it returns to 1.

    "xmas melodies" mode (10b)

      0=reset to tune 1
      1=play {"Oh Tannenbaum","Little Town of Betlehem"}
      2=music box mode - melodies see above
      3=silence

      (Be aware that here the Barcarole is not played together with the
       2 christmas songs.)

    "non-xmas melodies" mode (11b or active when pin 7,8 open)

      0=reset to tune 1
      1=play {DDR hymn?,melody 2,melody 3,"Barcarole"}
      2=music box mode - melodies see above
      3=silence

      (The Barcarole instead is played here as a 4th melody.)


I will check if we may contact Mr.Pirl for more information;possibly he still
has the Phoenix arcade board where my melody module came from.

From the melodies and sounds I have recorded a set of WAV samples for MAME.


                        MAY THE SOFTWARE BE WITH YOU!

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