On Wed, May 25, 2016 at 3:16 PM, Chris Fala via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
On Wed, May 25, 2016 at 2:56 PM, Dan Roganti via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
On Wed, May 25, 2016 at 1:47 PM, Chris Fala via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
On Wed, May 25, 2016 at 12:58 PM, Dan Roganti via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
On Wed, May 25, 2016 at 12:31 PM, Chris Fala via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
Would this help?
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
OK. So only one output can be on at any one time with this setup? Kind of a 74141 without the high voltage?
Funny thing, I Googled 4028 without any other text and the datasheet was the first search result.
Kinda, the 4028 doesn't have high voltage outputs either, but it's cmos so it has a wider operating voltage. As I mentioned in the other thread, they use bipolar output transistors on each output of the 4028 for this. This can waste more power, reducing the torque on the motors, they weren't thinking ahead, it's a toy, just make it cheap and get it out the door.