I have tried to color code the paths. Hope that works.
I'm not an electronics person and I don't really want to be one, nor am I really capable of ever being one, but I want to understand how this driver works. I mean, I understand the basics of what it does, but a couple things confuse me. You can see my notes on the photo above.
To the lower left of the Tiny13A controller, are 2 Resistors. I believe they are resistors, but I don't understand how the farthest one can go to ground, when the circuit is in the positive path? How can a resistor go to ground like that? I don't get it. AND, why are there two resistors? Why not just one? What are they resisting and why?
Also, in the far right hand side of the photo, (the back of the driver), the positive path goes to some little component (A cap of some kind??) and how does that work, or what does it do, because it too goes to ground.
Other than that, I can figure the paths for the 7135 chips and the path for the stars, for changing the modes. I just don't understand how a resistor goes to ground and works.
I have similar question before and I got this very informative inputs from Relic.
You can see from the schematic how the two resistors are connected. They are wired as a voltage divider.
Yes it is a capacitor on the lower right hand. It’s for voltage/spike conditioning and retention for limited time depending on the capacitance value.
The dead end pin on the MCU is the reset and is not used.
Yes the diode is for reverse polarity and it also lower the voltage applied to the MCU by the Vf of that diode.
Maybe others can provide you inputs or corrections if mine is not accurate. Cheers!
I think the resistors on the left are part of the low voltage protection. The MCU pin is connected between the 2 resistors, and their ratio determines at what voltage the MCU's sense pin is pulled low.
The resistors divide the voltage in the ratio 0.18:0.72.
0.18*3V=0.55V
The internal reference from the tiny analog-digital converter(adc) compares to his internal reference voltage of 1.1V.
If the voltage drops under a value which is selected in the tiny firmware it makes his battery protection things which are also programmed via firmware.
OK, that makes sense now. The diagram does not mean a thing, because I can't read them, but the words tell me exactly what I need. The resistors are the means of low battery cut out and the capacitor is basically acting to smooth out the spikes, if any.
The reason is I want to go ahead and make a driver myself for multiple XM-L using DrJones programmed MCU and using the same components off a 7135 driver. I want to lay the circuit out myself and then I can place things where I want, as long as the paths are where they should be. I can just use copper clad boards and etch them. I imagine using a stencil cut out and clear enamel will protect the areas I don't want etched. This way I can do as I like when I want a driver. Just cut it to size, etch it and solder the components on. I figure if I can actually do it, then most anyone could and we don't have to wait till the world ends just to get a driver we want, LOL. Instant SRK Driver.
I think the capacitor also keeps the Tiny13A powered for a while when switching modes as well, so it can differentiate between a short press and powering on. The 2 resistors drain the capacitor, so together they determine the short press time. Just guessing though, haven’t tested it at all, and I’m not really an expert on electronics.
Edit: The voltage divider is probably also be used to detect the short press (as the voltage on PB2 should be dropping while no power is supplied). So it might even have a timer for the maximum short press time, instead of relying on the resistors to drain the capacitor enough to reset the Tiny13A. Maybe I should take a look at the code for the driver some time.
The 105c does not detect the the difference between a short press and a long press. It uses on time memory. If it is on for less than ~2 sec it will switch modes at the power cycle. If it is on for more than ~2 sec mode memory will be set and it will return to that mode at the next power on.
First of all , No . Just because a keen mechanical mind like yours can picture wiring diagrams and will probably figure this stuff out , does not mean most anyone could .
If in fact you do figure out how to make and personalize your own drivers , your status as a modder will become the stuff of legend .
I have faith in both your perseverance and your ability to fully realize this dream and am expecting your eventual success .
The stars provide the means to ground a particular pin on the IC thereby selecting different mode groups. A jumper from the ground ring to the appropriate pin would accomplish the same thing. That’s how I plan to select the mode group on the 10mm driver board. Just last week a member pointed out that “does nothing” pin could be connected to ground via momentary switch to provide mode switching off the main current path using a small, low current switch. I haven’t checked but it might be the pin DrJones uses. At some point I’d like to do a thumb switched Micromag using this option.
