MOTM

Cool Paul! 

Any word on the CG module? What is the current place
and status of that project so far? Haven't seen an
update on it in a while (unless I missed something). 

Thomas

--- Paul Schreiber <synth1@...> wrote:

> I have finished my initial testing of the
> production-ready (almost, see 
> below) pc board
> set for the MOTM-730 VC Pulse Divider.
> 
> The board set consists of:
> 
> a) vertical-mounted jack board (uses new Switchcraft
> RoHS vertical jacks)
> This connects to CPU board via 34-pin ribbon cable
> 
> b) pot board, uses 2 of the Frac-style pots/knobs,
> connects to CPU
> via ribbon cable
> 
> c) switch board, has 4 NKK pcb mounted toggles,
> connects to CPU
> via header pins
> 
> d) CPU card, a 4-layer pcb ~ 3.5 " x 3.5", mixture
> of SMT and thru-hole.
> Contain s 2 PIC processors, 1 drives the 3-digit
> 0.56" LED display, the
> other does all of the physical counting/dividing.
> 
> e) LED display card, contains the 3-digit display,
> connects to CPU via 
> header.
> 
> The CPU requires the 6-pin MOTM-950-type power
> connection, as +5V
> at ~ 65ma is required in addition to the +-15V (at ~
> 10ma). I will not offer
> stuffed/tested CPU cards until after I have sold 100
> modules :)
> 
> I have spent ~ 20 hours checking this thing out over
> and over. I need to add 
> 3
> 10K pullup resistors on pins of the PIC controller,
> that were on the 
> prototype
> but someone (me? [cough]) had crossed them out and
> wrote 'Not needed'
> but guess what? NEEDED! The part has open-drain pins
> and needs a physical 
> pullup.
> 
> Other than that, it seems to work flawlessly. Input
> frequency can go up to 
> around
> 15Khz before 'glitching', although the primary
> application is firing off 
> multiple EGs
> when driven by LFOs or low audio range (say 100Hz
> CLK IN). The outputs are
> 0 to +5V square waves (or as close as we can get to
> square, depends on the 
> math)
> so they can be directly connected to EGs as a GATE
> input. The outputs are 
> driven by
> a 74HC244 HCMOS buffer and a 100ohm series resistor.
> 
> The '730 has 11 fixed divider outputs and 1 variable
> divider output. There 
> is toggle
> switch to select a '1/2 divide', meaning all of the
> divisors are scaled by 
> 2. Yes, this means
> *fractional division*, like dividing by 1.5, 2.5,
> 3.5, etc. When the toggle 
> switch is in the
> 'HALF' position, *all* divisors are affected.
> 
> The fixed divisor ratios are:
> 2, 3, 4, 5, 6, 7, 8, 9, 11, 12 and 16 in 'FULL'
> 
> The variable (in 'FULL') goes from 2 to 32. There is
> an 'INITIAL DIVIDE' 
> pot, and
> a CV input scaled for -5V to +5V full range, and a
> CV MOD attenuator.
> 
> There is an input jack called RUN/STOP and when
> pulled *low* (ie shorted to 
> ground)
> the unit resets. Can be used as a sync, but this
> input is *level sensitive*, 
> not edge.
> 
> Lastly, there is a "fun" output called STEPPED CV.
> This is a moderately 
> accurate (1%)
> 3-bit DAC connected to a 3-bit up-counter. This will
> generate a 
> positive-going stepped
> 'sawtooth' waveform. The step size can be 1 of 3
> switch-selected options: 
> 4th, 5ths or Octave.
> This output is *untrimmed*, but good enough for
> messing around. You can 
> always use
> an input attenuator to tweak in closer. The clock
> the counter uses is switch 
> selectable
> between the input clock or the divide-by-N output.
> 
> The 4th switch selects the positive or negative-edge
> to trigger the divider.
> 
> I already have production quantities of the display
> board, and will order 
> the switch, pot
> and jack production boards in ~ 1 week. This weekend
> I will add the 3 
> missing
> pullups and run the unit 72 hours straight at full
> speed to see if there are 
> other
> issues I missed. I will then order production CPU
> boards.
> 
> I am making 100 modules up, in 2 batches of 50. If
> these sell out, I will 
> make more.
> I can only afford parts for the first 100 right now
> (I just spent $4200 on 
> more parts
> yesterday and $1350 today).
> 
> I still need to design the front panel, and get a
> few prototypes made to be 
> sure I did not
> screw up mounting holes, the LED bezel cutout, etc.
> It is a *tight* fit, as 
> 3 of the boards
> stack up and they have to be perfectly aligned for
> the header pins to mate.
> 
> The cost of this module will be $399 and I am
> looking at a Oct 1st date for 
> the first 50.
> These will be *in stock, packed in boxes* the day
> they are announced.
> 
> OK, I'm pooped. Back to kitting and shipping this
> weekend. The MOTM-410
> and MOTM-120 kits are all done. Moving on to
> MOTM-420 and MOTM-440
> this weekend. I also have the pc boards in to make
> ALL of the MOTM-910 
> mults.
> 
> Paul S.
> 
> 


Thomas White
  Natural Rhythm
www.naturalrhythmmusic.com