44

A very simple bidirectional level translator can be made with a single N-mosfet: The mosfet used should be a model with a low Vgs threshold, so that it can have a relatively low Rds-ON (ON resistance) at the intended input voltage level (3.3v in this case). BSS138 in one such example, it has a Vgs-th of 1.5v max and is specified to have a low drain-source ...


36

The little piece of rubber you removed IS the connector. Elastomeric connectors look like a piece of rubber and are commonly called "zebra stripes" because the conductive carbon stripes in the rubber look like zebra stripes when viewed from the end. Image from Wikipedia:


26

The simplest option, and the one I'd recommend here, would be to use a microcontroller which supports USB natively and can be programmed with a USB DFU (Device Firmware Update) bootloader. One example of such a microcontroller is the ATmega32U4, as seen on the Arduino Leonardo; another is the ST STM32F103. Even if these microcontrollers are a bit more ...


23

You should learn what's realistic and what's not, and know your limitations. You come up with a price of 400 - 500 dollar for a couple of PCB's, but you don't seem to realize that these are just the PCBs, without any components, and without the cost of the design (which you are going to do). That's what an 8 to 12 layer PCB the size of a motherboard costs....


22

I hate nay-sayers more than anyone, and I'm all for undertaking difficult projects. BUT Designing and building a motherboard is Extremely difficult. Even if you already had great EDA software, and even if you already knew how to wire up the chips, the designing, building and testing process is about as hard as it gets. It's a bit like asking: "I'm trying ...


20

What is the role of the pnp transistor network? It's a differential voltage to current converter followed by a load (R34 and R35). The voltage between P+ and P- sets a voltage across R31. This (minus 0.7 volts) sets a voltage across R33 and that causes a current to flow out of the collector (largely irrespective of what load the collector has). Given the ...


14

If your goal is to design a modern PC, forget it really. Modern chips interface with busses like PCI express or high-speed differential busses. You can't breadboard this up, no way. Frequencies are from 100MHz up to several GHz. A breadboard will probably 'fall apart' at a couple of MHz (I can't even get my serial port to work at 3MBaud on the heavily used ...


12

It's a 7-segments display. Unlike the dot-matrix character displays kevlar refers to these are most often not intelligent module. Most dot matrix displays have an HD44780-compatible controller which you simply can write ASCII codes to, but a 7-segment LCD will often be just the glass, with connections for segments and a number of backplanes (often up to 4). ...


12

RS-422 and RS-485 use the same electrical interface specification. If you use that interface to build a bidirectional link on a single pair of wires, it's called RS-485, and it supports half-duplex operation. If you use that interface to build two unidirectional links on two pairs of wires, it's called RS-422, and it supports full-duplex operation. This is ...


11

The parallel port is great when you're using Windows 98 or DOS. All modern Windows operating systems have drastically changed how the parallel port interface works making it almost impossible to interface with anything other than a printer. And the parallel port is basically obsolete at this point anyway. Also, it's basically impossible to do any ...


11

Since the question seems oriented towards an IC that provides bidirectional level shifting, consider the Texas Instruments TXB010x family of parts: TXB0102 has 2 channels, TXB0104 has 4 channels, and TXB0108 has 8 channels. The stand-out feature of this family of ICs is that signal direction is automatically sensed, so a separate direction setting pin is ...


11

You can definetely use a PLC for this. Except, you don't want to change the PLC code for each "smoothie recipe". You should write a PLC application that reads recipes from any source, like sd cards, network storage, internal storage or even QR codes if you're feeling fancy. Often PLC's already have a feature for this, where a recipe is a set of parameters ...


10

The bead may have a higher reactance than resistance at low frequencies, which could cause things like undershoot spikes to increase rather than decrease. Most likely these spikes will cause the higher voltage 12V signal to go beyond acceptable limits for RS232 and possible damage the devices. The other connection are all at lower voltages.


10

Another thing you should consider is whether you actually need level shifting at all. Many chips have 5V tolerant input pins even when running at a voltage lower such as 3.3. The atmega CPU also interprets anything above 0.6*Vcc or 3V for an arduino as a logic high, so a 3.3V signal can directly drive an arduino pin with no level shifting. Assuming you are ...


9

The contacts are missing because they're not used. The A-key variant of the m.2 spec has provisions for display port signals while the E-key variant drops the display port and adds SDIO, UART and PCM (aka I2S), I'd bet those are the ones missing, especially as this is a dual use card (as it has both the A and E key slots present, any pins that differ between ...


8

This might help you a little bit. It will give you some idea of how much work goes into laying out a motherboard type PCB. But remember that this guy already knows all about high speed design, impedance matching, power supply distribution for high speed ICs, etc. YouTube: Extreme PCB layout - DDR3 Interface


8

universal protocol that is used by the likes of USB audio Sounds like the USB Audio Class specification. Is this conversion from output of ADC to USB data stream something which we can do, say, with a microcontroller? Some USB microcontrollers - NXP LPC17xx for example - have example code for USB Audio Class available.


8

Some microcontroller indeed only require a bypass cap to operate. Others require some kind of external clock, like a crystal, resonator, R-C, or a digital signal fed in from elsewhere. Newer micros tend to have internal clocks, but these are usually only good to a few percent accuracy. Boards with micros can be complicated because the system needs to do ...


8

In MCUs why do I need any other component except maybe a voltage regulator and an external clock? Some of the extra components are actually recommended, even for a minimum complexity design: Capacitors required by the voltage regulator for stability and load/line regulation performance. Protection devices like rectifier diodes, TVS diodes, etc. OTOH, ...


8

There is an Apple supplied driver for the CH340 included the recent versions of MacOS. "AppleUSBCHCOM".


7

Here is a digital domain solution. There is not a name for a component that fits the function you describe, but you can use a synchronizer together with a finite state machine. simulate this circuit – Schematic created using CircuitLab Synchronizer First, your finger is not synchronized to the clock, so the button is assumed to be an asynchronous ...


7

The RS-232 standard was originally specified to support connections between Data Terminal Equipment (DTE) such as computers, teletypes and video display terminals and Data Communications Equipment (DCE) such as modems and Automatic Calling Units (ACUs). At the time, DCE did not have any internal intelligence, so dedicated signals were designed into the RS-...


7

The above answer is quite good already, but an alternative approach if your micro-controller is too old/slow/dumb for even USB host or USB-OTG is to use a software (bit-banged) P/ATA interface with a P/ATA to SATA bridge chip. A commonly available one is the JMicron JM20330, the datasheet for which can be found here JM20330. The lowest common denominator PIO ...


6

Depends on the camera and how "raw" it is. A raw CMOS sensor usually spits data out in a 16-24 bit framed parallel bus. It's the same kind of system you see on the input of HDMI transmitters or some LCD panels. There is usually also an I2C interface for controlling the sensor. Other sensors use the same thing but transmit via LVDS (this is very common with ...


6

SATA is not a simple thing. SATA peripherals are offered through either PCIe to SATA converters, USB to SATA bridges, or the processor will have an on-chip peripheral. You need to go pretty high-tech to get an integrated SATA peripheral controller. Texas instruments does have some good USB to SATA bridges, great for external hard drive bays. I have ...


6

The rule of thumb is that signals travel at 2ns per foot in standard PCB material. That's roughly half as fast as the speed of light due to the effect of the PCB dielectric material. 180psec per inch is the same thing, and in metric that's 71psec per cm. Even if you are running with a 100MHz clock, thats 10ns per cycle. So assuming you have half of that as ...


6

This depend on which operating system you are using. If you are on linux, i would recommend you using gtk/glade. Install GCC and other basic requirement,then install GTK library Install Glade in your system which is used to make UI interface Choose you IDE, like eclipse is best in this case. Add path to your gtk libraries in eclipse Make UI in glade and ...


6

The trick with keyboard matrices like this is the fact that outputs can (on most microcontrollers) be in three possible states - HIGH, LOW, and High Impedance (Hi-Z). When an output is in Hi-Z mode it is effectively disconnected. So by setting three of the outputs to Hi-Z and the fourth output to LOW, and having the four inputs pulled up through resistors, ...


6

I assume you're talking about prototype boards here. Those are made complex to make prototyping and debugging easier: they tend to include as many features as possible, limited by the fact that they have to remain generic enough, and by the price tag. Typically, there will be at least some LEDs and buttons, proper clock and reset circuits, proper voltage ...


5

NXP make a range of I2C to UART bridge chips, http://ics.nxp.com/products/bridges/i2c.spi.slave.uart.irda.gpio/ http://ics.nxp.com/products/bridges/i2c.spi.slave.uart.irda.gpio/images/use.remote.gif Have a look at the SC16IS740.


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