Title: 7400contest entry: Usb device not recognized,
Post by: arupbsk on October 15, 2011, 08:53:52 pm
Post by: arupbsk on October 15, 2011, 08:53:52 pm
[attachment=1]000_0002[1].JPG[/attachment]
http://www.youtube.com/watch?v=xjQgtIIwS24 (http://www.youtube.com/watch?v=xjQgtIIwS24)
A simple device making fun of USB protocol. It gets all 4 pulses from USB data lines then USB controller talks to OS that USB device not recognized. At this time "Success" is shown in the display.
Did I said "Success". Well, success means positive thing, and in binary we call it 1.
So, 1 is displayed in the LT542 CA 7 segment display.
Disappointed? Were you expecting Text from a 7 segment. :P
I was experimenting with a 74LS47N and a CA display in breadboard. I have a few logic ICs in my box, and of them most are line drivers, D F/F, etc. Shame that I don't have a 4011 or 7400 (the NAND). I only had a 74LS47N that could display anything meaningful on a 7segment.
I searched Google on what can be made by 74LS47 without the typical application of BCD(binary) to Number(7 segment), counter and typicals.
I've found an interesting application of logic probe which shows 1 at high, 0 at low and nothing at HiZ.
Nice but I didn't had those other 7400 in hand or in box.
I was taking power from my USB port, as I often use it as reliable power source for breadboard experiments. (See the green LED at voltage source showing power ok)
Then I thought of making fun with the D+ and D- lines.
I already seen that if I connect an LED from VCC to any data pin, the LED flickers 4 times and then laptop shows USB not recognized. I tried to supply the information to the 7 segment.
As single line probing needs I needed to display either 0 or 1 to the display, I've grounded all BCD inputs except the LSB, which makes the display show 1 and 0 depending on the voltage on the LSB pin.
Then the fun begins, I've connected LSB to D+, and pulled up D- by a 1.5K resistor. And it showed a funny result.
The display flickers to 0&1 until USB device not recognized, and shows 1 when the device nonrecognition process completes. 1 means success. 1 means progress. So, it's a successful device which makes USB controller think USB device not recognized and when it gets success it shows 1 in the display to show success.
Is anyone eager to see a circuit diagram? Actually I've made this on breadboard without thinking of schematics, but if you read my article you'll know what will be the schematics. Anyways I'll upload a drawn schematics here tomorrow.
Good night.
EDIT: Schematics added.[attachment=0]
http://www.youtube.com/watch?v=xjQgtIIwS24 (http://www.youtube.com/watch?v=xjQgtIIwS24)
A simple device making fun of USB protocol. It gets all 4 pulses from USB data lines then USB controller talks to OS that USB device not recognized. At this time "Success" is shown in the display.
Did I said "Success". Well, success means positive thing, and in binary we call it 1.
So, 1 is displayed in the LT542 CA 7 segment display.
Disappointed? Were you expecting Text from a 7 segment. :P
I was experimenting with a 74LS47N and a CA display in breadboard. I have a few logic ICs in my box, and of them most are line drivers, D F/F, etc. Shame that I don't have a 4011 or 7400 (the NAND). I only had a 74LS47N that could display anything meaningful on a 7segment.
I searched Google on what can be made by 74LS47 without the typical application of BCD(binary) to Number(7 segment), counter and typicals.
I've found an interesting application of logic probe which shows 1 at high, 0 at low and nothing at HiZ.
Nice but I didn't had those other 7400 in hand or in box.
I was taking power from my USB port, as I often use it as reliable power source for breadboard experiments. (See the green LED at voltage source showing power ok)
Then I thought of making fun with the D+ and D- lines.
I already seen that if I connect an LED from VCC to any data pin, the LED flickers 4 times and then laptop shows USB not recognized. I tried to supply the information to the 7 segment.
As single line probing needs I needed to display either 0 or 1 to the display, I've grounded all BCD inputs except the LSB, which makes the display show 1 and 0 depending on the voltage on the LSB pin.
Then the fun begins, I've connected LSB to D+, and pulled up D- by a 1.5K resistor. And it showed a funny result.
The display flickers to 0&1 until USB device not recognized, and shows 1 when the device nonrecognition process completes. 1 means success. 1 means progress. So, it's a successful device which makes USB controller think USB device not recognized and when it gets success it shows 1 in the display to show success.
Is anyone eager to see a circuit diagram? Actually I've made this on breadboard without thinking of schematics, but if you read my article you'll know what will be the schematics. Anyways I'll upload a drawn schematics here tomorrow.
Good night.
EDIT: Schematics added.[attachment=0]