[vcf-midatlantic] Robots and Relays and Commodore

[Dan Roganti]

On Wed, May 25, 2016 at 1:47 PM, Chris Fala via vcf-midatlantic <
vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:

> On Wed, May 25, 2016 at 12:58 PM, Dan Roganti via vcf-midatlantic <
> vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
>
> > On Wed, May 25, 2016 at 12:31 PM, Chris Fala via vcf-midatlantic <
> > vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> >
> > > Would this help?
> > >
> > > http://www.ebay.com/itm/152084733487
> > >
> >
> >
> > ​almost,
> > that one has 6 outputs
> > you need one with 10 outputs​
> >
>
>
> Thought the C64 user port only had an 8-bit port. Where are the other two
> connected? The VIC has a few of the joystick port connected to the user
> port, but not sure what other outputs you can get out of the C64.
>


The C64 cartridge board used a cmos 4028, 4bit BCD decoder​ [Binary Coded
Decimal] which has 10 outputs.
Even though the interface uses a 4bit binary number, the 4028 only converts
the first 10 numbers, 0-9
This in turn drives each motor arranged in a bridge circuit inside the arm.
There are 5 motors in the arm  = base, shoulder, elbow, wrist, and gripper
Each pair of outputs drive one motor
The bridge circuit is wired for each motor with a split bipolar power
supply using batteries, B+, Gnd, and B-
Only one output on the 4028 is allowed to turn on
As there is no protection against faulty data switching on both signals and
causing a meltdown inside the arm
Dan