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Page 24

Create a folder on the local machine to act as the top level project folder – all of your C projects will be stored in sub-folders of this one. Within your top-level folder, create a folder called .json and create a custom settings.json file. This contains the details of the remote machine and the folders you want to use on the remote:

change .json to:.vscode

Create a folder on the local machine to act as the top level project folder – all of your C projects will be stored in sub-folders of this one. Within your top-level folder, create a folder called .vscode if you need to, and create a custom settings.json file. This contains the details of the remote machine and the folders you want to use on the remote:

Page 132

The number of different duty cycles you can achieve depends on the number of clock pulses in the total period. At 10MHz there are just two clock pulses and so just four duty cycles 0%, 50% and 100%.

change four to three

The number of different duty cycles you can achieve depends on the number of clock pulses in the total period. At 10MHz there are just two clock pulses and so just three duty cycles 0%, 50% and 100%.

The table on this page should read:

PWM Frequency	Number of clock pulses	Number of different duty cycles	Resolution in bits
10MHz	2	3	1.6
5MHz	4	5	2.3
2.5MHz	8	9	3.2
1.25MHz	16	17	4.1
625kHz	32	33	5.0
312.5kHz	64	65	6.0
156.25kHz	128	129	7.0
nkHz	20000/n	20000/n - 1	Log₂(20000/n -1)

In many applications 8-bit resolution for the duty cycle is considered the minimum acceptable and this sets the highest frequency to about 75kHz, which is high enough for most things.

For example, if you want to control a servo motor, see later, then you need a PWM signal with a frequency of 50Hz and at this frequency you can specify the duty cycle down to about 25 bits or around 40 million increments – more than enough for any real servo motor.

Page 148

The number of SPI buses a Raspberry Pi has depends on its model. The PiZero and Pi 3 have three SPI devices, but only SP0 and SP1 are available on the GPIO connector:

change SP0 and SP1 to SPI0 and SPI1

The number of SPI buses a Raspberry Pi has depends on its model. The PiZero and Pi 3 have three SPI devices, but only SPI0 and SPI1 are available on the GPIO connector:

Page 153

First connect pin 19 to pin 20 using a jumper wire and start a new project. The program is very simple. First we check that the SPI bus is loaded:

change 20 to 21

First connect pin 19 to pin 21 using a jumper wire and start a new project. The program is very simple. First we check that the SPI bus is loaded:

Page 242

Change

struct sockaddr_nl sa;
sa.nl_family = AF_NETLINK;
sa.nl_pid = getpid();
sa.nl_groups = 0;

change sa.nl_pid = getpid(); to sa.nl_pid = 0;

struct sockaddr_nl sa;
sa.nl_family = AF_NETLINK;
sa.nl_pid = 0;
sa.nl_groups = 0;

WIthout this change the program doesn't work but returns no error

Page 248 (Same error as page 242)

Change

struct sockaddr_nl sa;
sa.nl_family = AF_NETLINK;
sa.nl_pid = getpid();
sa.nl_groups = 0;

change sa.nl_pid = getpid(); to sa.nl_pid = 0;

struct sockaddr_nl sa;
sa.nl_family = AF_NETLINK;
sa.nl_pid = 0;
sa.nl_groups = 0;

Page 187

I have only just discovered (I have never used a DHT11!) that the DHT11 is not 100% compatible with the DHT22. The DHT11 uses a different encoding for the data. The DHT22 uses 16 binary for each of the values but the DHT22 uses a first decimal byte followed by a fractional byte. This means that for the DHT11 the decoding is just to take the first byte as the integer part and the second byte as the fractional part - and no need to divide by 10.

Also it has been pointed out the the 1ms start pulse is too low for some devices - increase it to 20ms if the device ignores you.

Page 290

The number of SPI buses a Raspberry Pi has depends on its model. The PiZero and Pi 3 have three SPI devices, but only SP0 and SP1 are available on the GPIO connector:

change SP0 and SP1 to SPI0 and SPI1

The number of SPI buses a Raspberry Pi has depends on its model. The PiZero and Pi 3 have three SPI devices, but only SPI0 and SPI1 are available on the GPIO connector:

Page 298

First connect pin 19 to pin 20 using a jumper wire and start a new NetBeans project. The program is very simple. First we initialize the library and the SPI bus:

change 20 to 21

First connect pin 19 to pin 21 using a jumper wire and start a new NetBeans project. The program is very simple. First we initialize the library and the SPI bus:

If you are looking for downloadable project files - there aren't any. The reason is that Android Studio changes too often to keep the details up to date. What would happen is that any project file would generate messages about being out of date almost as soon as it was published. Instead here are source code listing that you can copy and paste into a new project. This is a much better way of trying out code in Android Studio.

So start a new project and paste the code into the appropriate file.

Custom

Pages 292-

Update: 3 March 2020

NetBeans 8.2 seems to have stopped working under Raspian (Buster). It installs but wont open a new project. It still works under Windows 10.

As NetBeans 11.2 works perfectly on the Pi there is no reason to continue to try and make the unsuported version work. Follow the instructions to install it on the Pi given below.

The NetBeans 8.2 plugin library is include but you have to enable it. Make sure you click the check for newest buttons after enabling it.

Select the C++ plugin and install it.

After this you can run NetBeans - the script in the bin directory - as usual.

I understand the the Apache team are working on native support for C/C++ but it probably wont be complete until version 12 some time this year.

Original Information

NetBeans has been moved to Apache and Oracle are slowly moving the source code of the project to its new home. At the moment they haven't made the C/C++ code available but the old plug in works. What this means is that you have two choices. However before this you need to make sure you have a JDK installed:

NetBeans is a Java program that will work on any machine that supports a Java Virtual Machine (JVM) and the Pi comes with a JVM already installed as part of Raspbian. If you are installing NetBeans on a PC or a Mac you need to check that Java is installed and if it isn't you need to install it.

To check open a command prompt, this works for Windows, Linux and Mac OSX, and type:

java -version

If you don't see a listing something like:

openjdk version "11.0.3" 2019-04-16 LTS
OpenJDK Runtime Environment Corretto-11.0.3.7.1 (build 11.0.3+7-LTS)
OpenJDK 64-Bit Server VM Corretto-11.0.3.7.1 
                               (build 11.0.3+7-LTS, mixed mode)

then either Java isn't installed or it is miss configured. Consult the documentation on the website of the JDK you are using. You can use any JDK from 9 though 12.

If you haven't got Java working there is no point moving on to install NetBeans as it simply will not work.

You can stay with NetBeans 8.x and use the original Oracle downloads and installers. This makes it very easy to install and it all works exactly as described in the book. There is no particular disadvantage of this approach as there is nothing in NetBeans 11 that you need to work with C/C++.

You can find the 8.x series of NetBeans by following the Older releases link on the Apache download page.

It is currently here but given the changes occurring it could well change and you might need to visit what ever the current download page is.

A direct link to NetBeans 8.2 can be used but it might change - if so check out the new main download page.

As described in the book download the C/C++ version or the complete version.

The second option is to download and install the latest version of NetBeans - 11.x at the time of writing.

If you do this it doesn't have the C/C++ option included and you have to set it up so that it makes use of the 8.2 plugin.

The procedure described below works for Raspian, Linux, Windows or OSX.

Go to the NetBeans web site https://netbeans.apache.org and navigate to the download page. Select the latest version and download the zip listed as "Binaries". Its name should be something like:

netbeans-11.1-bin.zip

according to the version number. You will also see installers for various operating systems at the time of writing there isn't an installer for Raspian and the other installers often fail to find the installed JDK - working with the binary is just as easy.

After the download is complete you have to extract the files in the zip to a suitable directory. If you are the only person going to use NetBeans then your Linux home directory or Program Files under Windows is suitable. Extract all of the files into the directory.

Navigate to the directory and then netbeans/bin and run the file netbeans for a Linux installation or netbeans.exe or netbeans64.exe for a 32 or 64 bit Windows installation. These small programs install NetBeans and subsequently runs the IDE after installation. Run it in a terminal, accept the license agreement and wait while it installs.

At this point you will have a working NetBeans IDE and you can use it to create Java, PHP and JavaScript programs but, at the time of writing the C/C++ plugin is not installed and an upgraded version isn't available. As a temporary solution you have to use the original 8.2 plugin - this is likely to change as the NetBeans project develops.

All you have to do is use the Tools | Plugins menu option and, in the Settings tab of the dialog box that appears enable the NetBeans IDE 8.2 update center. If it isn't in the list for any reason add:

http://updates.netbeans.org/netbeans/updates/8.2/uc/final/distribution/catalog.xml.gz

Next go to the Available Plugins tab and click the Newest button to update the list. It is also worth selecting the Updates tab and click the Check For Updates tab to make sure everything is up-to-date before installing the plugin. Search for or find the C/C++ plugin, select it and click the install button. Follow the installers instruction and allow it to install and upgrade everything it wants to.

If installation fails make sure you have all of the other plugins up-to-date and try again or check to see if it works after up-date.

If you are using NetBeans under Raspian you can add it to the Programming group in the menu. All you have to do is select Preferences, Main Menu Editor. Then select the Programming group and select New Item. Fill in the dialog that appears as shown:

The command is:

/home/pi/netbeans/bin/netbeans

adjusted to reference your home directory rather than that of user pi if necessary. After this you can run NetBeans from the menu. If you want to add an icon then simply right click on the menu item, select properties and click on the default icon. Next simply navigate to /home/pi/netbeans/nb/ and select netbeans.icon.

If you are using NetBeans on a Pi then you can now create a new C/C++ project as described in a later section. If you are using NetBeans on a deskopt machine you now need to setup a remote connection to a Pi to work with C/C++.

Page 124

All variables named temp1 should be temp.

So the bottom part of the page should read:

All we now have to do do is to put the two bytes together as a 16-bit integer. As the micro:bit supports a 16-bit int we can do this very easily:

int16_t temp= (b2<<8 | b1) ;

Finally we need to convert this to a floating point value. As already discussed, the micro:bit doesn’t support this in hardware. As all we really want is two digits to give the tens and two digits to give the fractional part it is easier to work in integer arithmetic using temperature*100:

temp = temp * 100 / 16;

This gives us an integer value that represents the temperature in hundredths of a degree centigrade, e.g. 25.45C is represented as 2545. Notice that this only works because int16_t really is a 16-bit integer. If you were to use a 32‑bit int:

int temp= (b2<<8 | b1);

then temp1 would be correct for positive temperatures but it would give the wrong answer for negative values because the sign bit isn't propagated into the top 16 bits. So if using a 32-bit integer, propagate the sign bit manually:

int temp=(b2<<8 | b1); if(b2 & 0x80) temp=temp | 0xFFFF0000;

Assuming we have the temperature in 100ths in temp, we can now display it on the micro:bit's LED matrix. First we need to convert it into a string:

char buff[10];

Note: It is correct in the final listing.