Fix Sb Ports For Arduino El Capitan

Introduction: Extend the Ports of Arduino Using IC 74HC595N

The chips used on the Arduino board (the ATmega8 and ATmega168) have three ports: B (digital pin 8 to 13) C (analog input pins) D (digital pins 0 to 7) Each port is controlled by three registers, which are also defined variables in the arduino language. The DDR register, determines whether the pin is an INPUT or OUTPUT. Apr 30, 2018 Link: arduino com port, arduino com port not found ubuntu, arduino com port not found, arduino com port not found mac, arduino com port mac, arduino com port settings. Oct 22, 2015  After the update to El Capitan, I can't see the serial port for my nano clones, CH340 equiped:-) I tried this command: sudo nvram boot-args='kext-dev-mode=1' without success, doesn't work with El capitan released (but seems ok with Yosemite and El capitan beta versions).

Introduction

Many of us face problem when try to connect more sensors and output devices in arduino. Because there is no enough ports to connect.To overcome this some may go to arduino Mega.We need not go to Arduino Mega to have extended ports.Here is a solution to extend the ports of Arduino Uno. We extend the ports of arduino using IC 74HC595N which is ashift Register for Serial in and Parallel out.This register IC takes 3 pin input and gives output at 8 Pins. Thus this extends 3 pins to 8 pins.The extended pins are used only as output port to connect output devices such as LED,LCD,Bar Graph Display,Piezo Buzzer etc.

Step 1: Components Required

  • Arduino Uno
  • LED --------------------- 8
  • Resistor 100ohm ---- 8
  • IC 74HC595N Shift Register

Step 2: Operation of IC74HC595N

How does it extends ports?

Arduino combines the data to be sent to output devices in serial format and transmit the serial data to IC 74HC595N.The IC shifts the serial data and make its available at the parallel output pins of IC 74HC595N.The serial formatting of data to various output device is done by shiftwrite function given in the coading.

For example

10101100 these numbers represents 8 bit data.Each number in 8 bit represents the status of eight LED'S.

One(1) indicates LED is ON.

Zero(0) inducates LED is OFF.

So there are 8 LED'S connected to the output data pins of IC74HC595N.So each bit in 8 bit data has to be available at the output pins of IC74HC595N.To get the 8 bit data available at output pins.The 8 bit data has to be shifted 8 times so that each bit will be available at 8 output pins of IC74HC595N.So eight clock pulses are required to shift 8 bit.In order to get data without error the shifting has to be done in nano Seconds(ns).So high frequency clock is requied.This clock is generated by arduino code itself.The communication between electronic devices is called as Digital Communication.Arduino is also a digital device because it deals with digital data that is Zeros and Ones.So in digital communication every data has to be sent in frame format.So this 8 bit data is to be sent in frame format.This is also done by arduino code itself.So with the proper coading you can connect output devices at the parallel pins of IC74HC595N.The diagram explanation is given above.I have also attached diagram explanation in zip format.

Step 3: Schematic Diagram

The Schematic uses three arduino pin

DataPin

Serial data is sent through this DataPin.

ClockPin

It generates clock pulse that is needed to shift data

LatchPin

This pin is used to toggle so that shift register shows 8 bit data on output.

Step 4: Programming

Every command of the following programme is explained Here

shiftWrite(Pin, State):

This function is same as digitalWrite function. It makes Pin HIGH/LOW. Usage is as same as the digitalWrite function.
increament()

This function is designed for LED array on shift register, LED starts glowing from LED 0 to LED 7 and as all gets ON these starts getting OFF from LED 7 to LED 0.

OneByOne():

This function is similar to above mention increment() function but the difference is that in this function only one LED glows at a time. So in this function LED starts glowing from LED 0 to LED 7 and in the reverse order too.

AllHigh()

This function makes all output pins HIGH.

Fix Sb Ports For Arduino El Capitan

AllLow()

This function makes all output pins LOW.

SOS()

This function repeats HighAll() and LowAll() function 10 times with an interval of 100ms between two steps.

Step 5: Program Code:

I have attached Coding in RaR format Download and open it in arduino IDE

I have also attached in txt format

Because the program is slightly large.

Attachments

  • 74HC595N.txt

Step 6: Video

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Arduino port manipulation is the “close to the metal” way of reading and writing bit.

In this tutorial we take a look at how it’s done.

Port manipulation?

It is undeniable that the ease of access and usage of the Arduino library is a key factor in its success. More specifically, you have access to functions such as pinMode and digitalRead / digitalWrite which makes it incredibly easy to control individual pins.

Under the hood though, it is not how a micro-controller works. You cannot control an individual bit. Instead, you have to read and write and entire “port”. On a 8 bit micro-controller, this means reading and writing a port of 8 bits. Port control is buried deep in the Arduino documentation so let’s review how it works here with some simple examples.

The Atmega328 pinout

If you look at a typical Arduino Uno pinout, you will notice that some pins are labelled “PB0” or “PD1”. These are the 8 bit ports that are part of the Atmega328 chip powering the Uno.

Straight from the documentation, you can read for instance:

Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port D output buffers have symmetrical drive characteristics with both high sink and source capability. As inputs, Port D pins that are externally pulled low will source current if the pull-up resistors are activated.
Side note: As a matter of fact, ALL Arduinos running the Atmega328 will behave exactly the same. That means the Arduino Uno, Arduino Nano, Arduino Mini & Pro Mini are pretty much the exact same product, in different form factors.

Controlling the port

Controlling the port with Arduino is really easy. There are two registers you need to know about:
  • DDRx (e.g. DDRD for port D) is the register that controls if pins are input or output. (0=input, 1=output)
  • PORTx (e.g. PORTD for port D) reads or write the bits.

For example:

is equivalent on an Arduino Uno to:

INPUT_PULLUP using port manipulation

“pinMode” in Arduino lets you select INPUT, OUTPUT, or INPUT_PULLUP. Since writing the DDR port only allows you to select input or output, there’s a trick to activating INPUT_PULLUP mode on a pin: you must set it to input, then write a high value to it. So instructions like:

Fix Usb Ports For Arduino El Capitan Download

…will set the whole port D as input pullups. In fact, this is very similar to the first revisions of the Arduino library where you had to do “pinMode(x, INPUT)” then “digitalWrite(x, HIGH)” to activate INPUT_PULLUP mode.

What are the benefits of direct port manipulation?

Direct port manipulation has several advantages:

  • You are closer to the metal: pinMode, digitalRead and digitalWrite perform underlying port manipulations.
  • You can write or read data simultaneously. Using digitalWrite for a pin then for another introduces a delay that is completely absurd when reading or writing parallel data. It might even creates some issues in very timing sensitive devices.
  • Code is smaller. Because you don’t introduce the additional layer of traditional Arduino functions, resulting code can be smaller.

Of course, the drawback is that the code becomes less readable in some cases. A mix of port manipulation and traditional Arduino function calls might be the key to a good program.

Fix Usb Ports For Arduino El Capitan 1

Example of usage:

Fix Sb Ports For Arduino El Capitan Download

Illuminating the LEDs like in the video above would mean a lot of code to be written with Arduino functions. Port manipulation makes this task incredibly compact code wise. See below the code for this example:

Conclusion

If your project needs to manipulate serial to parallel or parallel to serial ICs, BCD decoders, or any other ICs that needs to read or write data on more than a bit; using direct port manipulation is often beneficial.

For readability’s sake, do not overlook the good old Arduino bit manipulation functions though, as they are good enough for most usage.