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I recently bought mares Puck (not puck pro) and I'm quite happy with it, but the cost of PC cable is insane (it costs more than I paid for new Puck
"Originally Posted by BryscusThis works as expected.
1. When the Puck is either not connected or not in PC mode, the green light will be on. This is because the Puck tri-states (lets float) its DIO pin. Without anything to pull the DIO pin high, the 100k resistor pulls the NAND inputs low (pins 1 and 2) which then drive pin 7 high. If the Drak is not in SUSPEND (sleeping or not enumerated on the USB) then pin 12 of the CP2102 will be low which causes current to flow through the green LED, lighting it."
"Originally Posted by BryscusThis also works
2. When the Puck is connected and put into PC mode, then the DIO pin is pulled high. This pulls NAND inputs high which causes pin 7 to be pulled low. This lights the red LED because current now flows from CP2102 pin 11 to pin 7 through the LED."
"Originally Posted by BryscusThis doesn't work. I checked pin 26 voltage while software is tying to communicate with puck. It doesn't go low, so maybe there is something wrong here?
3. The PC then sends a message to the Puck. Pin 26 is pulled high normally (its idle state) which allows DIO to be pulled high. When Pin 26 is pulled low (when sending data), current flows through the S7 diode pulling the DIO pin low (to about the forward voltage of the diode)."
"Originally Posted by BryscusRest didn't work, here is what happens:
4. When receiving data, pin 26 stays high, and DIO is toggled by the Puck computer. When DIO is high, pin 7 is low and pin 5 is idling high. This makes pin 25 high. When DIO is pulled low by the Puck, pin 7 (pin 6) is high and because pin 5 is also high pin 25 is toggled low.
This setup uses TX pin 26 as a switch for bi-directional data transfer - when held high, RX can receive. When data is sent and received the LEDs should flash from green to red based on the current state of the DIO line. This circuit also creates something like an open collector connection between the two devices. The data transfer speed is 38400 baud. I'm not sure if just using an open-collector output tied to the RX line would work. The PC would then have a loop-back where it received everything it sent. This depends on the computer software and what it does with the extra data."
1. USB cable connected: red diode OFF, green ON
2. Puck connected in PC mode: red diode ON, green OFF
3. I run mares connection wizzard, when it tries to find Puck red diode goes down (green is off all the time) so i think pin 12 goes high.
4. Software goes "thinking" for few moments and than displays that device is not connected. However i think that "something" is happening because if I do those steps without puck connected software instantly displays information that device is not connected.
Has anyone done more research? maybe there are some adjustments that should be made in this schema?
). Since last time I changed one thing now I'm using SN74HC132N Schmitt NAND (previous was not able to operate at ~3V). That made a little progress but the circuit still doesn't work Situation now looks like this: and back tu point 2. ) all connections and I think they are correct.
I think that is the answer. BAT42 is a Schottky diode unlike 1N4148
I'm slowly out of options, circuit seems to be simple and I think that I made no mistake. Only difference now is that I'm using 74HC132N instead 74AC132N but I don't know the difference between them.
