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14

Stick the headers through your main board from the bottom, with the plastic on the bottom. Set your Teensy on top, with the headers going through its holes. Solder the Teensy to the headers. Using a small screwdriver, pry the plastic off the headers. You'll be surprised how easy it comes off. Solder the headers to the main board. Trim headers as ...


10

Have you considered simply surface-mounting the module onto your PCB? The header holes are big enough for solder to flow down and wet onto the main board. Or you could use some solder paste and reflow on a hot-plate or an oven.


7

There are indeed AVR boards with integrated USB edge connectors, e.g. the DigiSpark: Would the DigiSpark suit your purpose? That would depend, the microcontroller in it is the ATtiny85, would that be sufficient for you? The project description mentions a possible use as "fool your friends by programming it to be a USB keyboard and turn their caps lock on ...


7

The USB in the AT90USB162-16AU has its own clock circuitry. The 48 MHz USB clock is generated with an on-chip Phase Locked Loop (PLL). The PLL in this case always multiplies its input by 6. Thus the PLL clock register must be programmed by software to generate an 8MHz clock on the PLL input as shown below: So if an 8 MHz crystal is used, the PLL clock ...


6

A USB port can supply at least 100 mA without USB enumeration, and 500 mA or more after successful enumeration. Most PCs (and laptops) don't actually restrict the current in either mode, and you can often draw more than 500 mA, but that is not recommended (or guaranteed).


5

I did not figure out how to do it from teensyduino (aside from having it also be recognized as storage in addition to keyboard). But I did find out that if you skip the teensyduino and just edit C files and compile them, then manually load the hex file to the board it work just fine as a keyboard on android and PC. Here is the page I used most to get it set ...


4

What you describe is the standard way of scanning a matrix keypad. Essentially you are using the outputs as open-collector / open-drain (because you switch between output+low and input). For chips that do not have this possibility a diode can be put in series. Switching a pin between input and output is totally safe and valid, it is done all the time, when ...


4

A Kapton tape layer between the two boards to prevent accidental short circuits. (Must be Kapton to withstand soldering temperatures) Just use resistor legs (or other sources of tinned wire) through each hole, soldered both sides, trimmed to length. This isn't something you'll do in any quantity, or else it would be worth re-laying out the board (or cloning ...


3

You've select waveform mode 5 (WGM22=1, WGM21=0, WGM20=1). This means: "Phase Correct PWM where OCR2A is the TOP value". This means that the timer will count up to the value in OCR2A and then count back down to zero. The OC2A pin won't have an output in this mode, and the OC2B pin will be set when counting up on a compare match between OCR2B and TCNT2 and ...


3

Technically, it is possible. The board already has a Micro-AB port, and the MCU on it supports OTG. But all the examples now given are configuring it as a device. So you may need some coding to make it a host. Update: And, thanks to @PkP, he find their is a example for USB host in the MCU's datasheet, section 41.7.


3

I doubt that you'll get what you want, but let's run the numbers. The solenoid can be rated for continuous operation, and will dissipate 2 watts. I note that the link you provided allows the specification of duty cycle and voltage, so I assume you're going to order the 3-volt, continuous option. You can calculate the current needed, it's just 2 watts / 3 ...


3

No. It's very unlikely that the proposed I2C bus would work. Very few devices support high speed I2C, as John had mentioned in his post. The manual for K20 family mentions only 100 kbit/s for I2C (p. 1169 in the PDF). I2C was designed only for communication over short distances (usually within a circuit board). It can be extended, but it usually comes ...


3

There is a highspeed specification for I2C, you can read about it here: http://www.i2c-bus.org/highspeed/ However, it needs special hardware and very few devices support it. I2C fast mode supports up to 1MHz, but you have to be very careful about how much capacitance you have on the bus. Two meters of wire is likely a non-starter. So I would consider ...


3

To understand all of this stuff, take a look at "Table 18-1. Equations for Calculating Baud Rate Register Setting" from the datasheet on page 189. The equation you suggested you found in some example code UBRR1 = (F_CPU / 4 / baud - 1) / 2; ... is kind of close to the equation for Asynchronous Double Speed mode (U2Xn = 1)... but not exactly. If you know ...


3

An unsigned char should always be 8-bits or a single byte. Forget that it is a 'character' but rather just a number data type that is the same size as our registers. Since we are passing in a number that could possibly be as large 12 bits, our function is accepting a data type that is large enough for baud (unsigned int). This could either be 32 or 16-bits (...


3

Have your board made with a cutout that the "teensy" board fits into, and through-holes around the edge of that. Make a bunch of U shaped wires to make the electrical and physical connection. Add epoxy or hot-glue after soldering if you want more physical connection.


3

Get a set of press-fit headers (e.g. these) instead. The loops press against the sides of the holes in order to make a decent connection. Note that they may come loose when the board is removed from the breadboard though.


3

The pin marked Vin on the TeensyLC board is equivalent to the Vin pin on the Arduino. The pin is designed to be used to supply power to the Teensy board. However based on the description page to which you have linked, it appears that the Vin pin can also be used to supply 5V to an external circuit when the USB port is connected. As far as I can tell (and you ...


3

Your proposed plan will not work. Never mind synchronization. The levels between the DAC and ADC will not match. There is noise that will be picked up and/generated in the conversions. Besides that, your "encryption" will generate sharp edged signals. The sound cards will (must) round those sharp edges. Your digital "encryption" will be turned to mush. ...


2

I believe what your asking for is a USB 'A' Male connector, like this: Yes it is feasible to replace the USB Mini 'B' connector that's on the Teensy, however the 'A' connector is much larger so you will have trouble attaching it to the PCB board without damaging or shorting something. I don't know if the Teensy is open source, but if so you could alter ...


2

If the chip doesn’t use any special functions of those pins (for example, UART on pins D0 and D1 or I2C on A4 and A5), you can connect to any pin on a Teensy. You would of course have to modify the library with the correct pin values. Some libraries let you specify the pins at run time. Of the pins you mention, D2 has an interrupt attached, D10 has PWM, and ...


2

I figured it out. The problem was in the 32bit vs 16bit architecture of the Teensy vs Arduino boards. In a 32 bit environment, an int is 32 bits. In a 16bit environment, an int is 16 bits. At least, that's what I'm seeing in Teensy (32bit) vs Arduino (16bit). This makes a difference in the bit shifting / 2's complement calculation done for the X, Y, and Z ...


2

Since I also have worked on the same type of displays, I must say that you are in the right direction. But the thing is, connectors highly depend on the type of wires that are connected to both led strip and connector. Your wire must have enough gauge rating wire so that it would support such huge current. Here you can find what type of wires to use for ...


2

Turns out this happens when the DDR register is set to input instead of output.


2

The STP16CP05 (Datasheet) is a constant current SINK, where the logic's voltage level and the led's voltage level are separate. Essentially, the outputs are npn transistors or n-channel mosfets controlled by the STP16CP05's logic. Each STP16CP05 can be powered by 3.3v, for communication from a 3.3v micro, and will only use ~4.5mA of power from that 3.3v ...


2

Yes, you can do this with a resistor divider. We usually think of a resistor divider as multiplying a voltage by some value less than 1, meaning scaling relative to ground. However, a resistor divider can be set up to scale relative to any particular voltage. In your case, you can scale the voltage about the 3.3 V supply instead of about ground. Overall, ...


2

According to this post on the geekhack forum: R61 trackpoint pinout (with PTPM754DR) « Reply #20 on: Wed, 23 January 2013, 08:04:09 » DATA RST BTN1 BTN2 BTN3 CLOCK GND VCC When connecting to PS/2 interface, DATA and CLK should be pulled up to vcc using 4k7 resistor, RST to GND using 100k resistor and RST to vcc using 2.2uF ...


2

I'll do my best to address the various sub-questions: Is this EPROM faulty or failing? Perhaps. There is certainly abnormal behaviour, based on those Salae analog port traces. However I have never been very comfortable about the limited resolution of that feature (it's better than nothing, but nowhere near as good as a real scope, imho). Perhaps this ...


2

The output impedance of 32 kohm can be a significant problem when attached to the ADC input on the MCU. Table 24 entitled "16-bit ADC operating conditions" states that the input impedance is typically 2 kohm and this will screw up any measurement from a source that has an output impedance of 32 kohm. You might get away with a parallel capacitor - the ...


2

Yes. Impedance will be a problem as well as DC offset and sampling range. From the documents you linked, the Teensy wants the impedances on its inputs to be below 5K. The ADXL326 has 32K resistors on its outputs, so you won't meet the Teensy's requirements just connecting the two together. You will need to buffer the outputs from the ADXL326 before ...


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