Merge branch 'master' into JamesH65-patch-1#ConfigTxtUpdate

Author: JamesH65

configuration/config-txt/README.md

@@ -2,7 +2,7 @@
 
 The Raspberry Pi uses a configuration file instead of the [BIOS](https://en.wikipedia.org/wiki/BIOS) you would expect to find on a conventional PC. The system configuration parameters, which would traditionally be edited and stored using a BIOS, are stored instead in an optional text file named `config.txt`. This is read by the GPU before the ARM CPU and Linux are initialised. It must therefore be located on the first (boot) partition of your SD card, alongside `bootcode.bin` and `start.elf`. This file is normally accessible as `/boot/config.txt` from Linux, and must be edited as [root](../../linux/usage/root.md). From Windows or OS X it is visible as a file in the only accessible part of the card. If you need to apply some of the config settings below, but you don't have a `config.txt` on your boot partition yet, simply create it as a new text file.
 
-Any changes will only take effect after you've rebooted your Raspberry Pi. After Linux has booted, you can view the current active settings using the following commands:
+Any changes will only take effect after you have rebooted your Raspberry Pi. After Linux has booted, you can view the current active settings using the following commands:
 
 - `vcgencmd get_config <config>`: this displays a specific config value, e.g. `vcgencmd get_config arm_freq`.
 

configuration/config-txt/conditional.md

@@ -1,16 +1,18 @@
 ## Conditional filters in config.txt
 
-When a single SD card (or card image) is only being used with one Pi and one monitor, it's easy to simply set `config.txt` as required for that specific combination and keep it that way, amending only when something changes.
+When a single SD card (or card image) is being used with one Pi and one monitor, it is easy to set `config.txt` as required for that specific combination and keep it that way, amending it only when something changes.
 
-However, if one Pi is swapped between different monitors, or if the SD card (or card image) is being swapped between multiple Pis, a single set of settings may no longer be sufficient. Conditional filters allow you to that certain sections of the config file are used only in specific cases, allowing a single `config.txt` to create different configurations when read by different hardware.
+
+However, if one Pi is swapped between different monitors, or if the SD card (or card image) is being swapped between multiple Pis, a single set of settings may no longer be sufficient. Conditional filters allow you to define certain sections of the config file to be used only in specific cases, allowing a single `config.txt` to create different configurations when read by different hardware.
 
 ### The `[all]` filter
 
-The `[all]` filter is the most basic filter: it resets all previously set filters and allows any settings listed below it to be applied to all hardware.
+This is the most basic filter. It resets all previously set filters and allows any settings listed below it to be applied to all hardware.
+
 
     [all]
 
-It's usually a good idea to add an `[all]` filter at the end of groups of filtered settings to avoid unintentionally combining filters (see below).
+It is usually a good idea to add an `[all]` filter at the end of groups of filtered settings to avoid unintentionally combining filters (see below).
 
 ### The `[pi1]` and `[pi2]` (etc.) filters
 
@@ -22,7 +24,7 @@ Any settings below a `[pi2]` filter will only be applied to Pi 2 hardware. The `
     [pi3]
     [pi0]
 
-These are particularly useful for defining different `kernel`, `initramfs`, and `cmdline` settings, as the Pi 1 and Pi 2 require different kernels. They can also be useful to define different overclocking settings for each, since they have different default speeds. For example, to define separate `initramfs` images for each:
+These are particularly useful for defining different `kernel`, `initramfs`, and `cmdline` settings, as the Pi 1 and Pi 2 require different kernels. They can also be useful to define different overclocking settings, as the Pi 1 and Pi 2 have different default speeds. For example, to define separate `initramfs` images for each:
 
     [pi1]
     initramfs initrd.img-3.18.7+ followkernel
@@ -50,20 +52,20 @@ This will print something like this:
 
     device_name=VSC-TD2220
 
-You can then specify settings that apply only to this monitor like so:
+You can then specify settings that apply only to this monitor:
 
     [EDID=VSC-TD2220]
     hdmi_group=2
     hdmi_mode=82
     [all]
 
-This forces 1920x1080 DVT mode for this monitor, without affecting any other monitors.
+This forces 1920x1080 DVT mode for the specified monitor, without affecting any other monitors.
 
-Note that these settings apply only at boot, so the monitor must be connected at boot time and the Pi must be able to read its EDID information to get the correct name. Hotplugging a different monitor after boot will not reselect different settings.
+Note that these settings apply only at boot, so the monitor must be connected at boot time and the Pi must be able to read its EDID information to find the correct name. Hotplugging a different monitor into the Pi after boot will not select different settings.
 
 ### The serial number filter
 
-Sometimes settings should only be applied to a single specific Pi, even if you swap the SD card to a different one. Examples include licence keys and overclocking settings (although the licence keys already support SD card swapping in a different way). You can also use this to select different display settings even if the EDID identification above isn't possible for some reason, provided that you don't swap monitors between your Pis - for example, if your monitor doesn't supply a usable EDID name or if you're using composite output (for which EDID cannot be read).
+Sometimes settings should only be applied to a single specific Pi, even if you swap the SD card to a different one. Examples include licence keys and overclocking settings (although the licence keys already support SD card swapping in a different way). You can also use this to select different display settings, even if the EDID identification above is not possible, provided that you don't swap monitors between your Pis. For example, if your monitor doesn't supply a usable EDID name, or if you are using composite output (for which EDID cannot be read).
 
 To view the serial number of your Pi, run the following command:
 
@@ -73,7 +75,7 @@ The serial will be shown as a 16-digit hex value at the bottom. For example, if
 
     Serial          : 0000000012345678
 
-Then you can define settings that will only be applied to this specific Pi like so:
+then you can define settings that will only be applied to this specific Pi:
 
     [0x12345678]
     # settings here are applied only to the Pi with this serial
@@ -82,7 +84,7 @@ Then you can define settings that will only be applied to this specific Pi like
 
 ### Combining conditional filters
 
-Filters of the same type replace each other, so `[pi2]` overrides `[pi1]`, as it's not possible for both to be true at once.
+Filters of the same type replace each other, so `[pi2]` overrides `[pi1]`, because it is not possible for both to be true at once.
 
 Filters of different types can be combined simply by listing them one after the other, for example:
 

configuration/config-txt/memory.md

@@ -2,9 +2,9 @@
 
 ### gpu_mem
 
-GPU memory in megabytes: `gpu_mem` sets the memory split between the CPU and GPU; the CPU gets the remaining memory. Theinimum value is `16`, and the maximum value is `192`, `448`, or `944`, depending on whether you're using a 256M, 512MB, or 1024MB Pi. The default value is `64`.
+GPU memory in megabytes. This sets the memory split between the CPU and GPU: the CPU gets the remaining memory. Minimum value is `16`; maximum value is `192`, `448`, or `944`, depending on whether you are using a 256M, 512MB, or 1024MB Pi. The default value is `64`.
 
-Setting `gpu_mem` to low values may automatically disable certain firmware features, as there are some things the GPU simply can't do with too little memory. So if a certain feature you're trying to use isn't working, try setting a larger GPU memory split.
+Setting `gpu_mem` to low values may automatically disable certain firmware features, as there are some things the GPU cannot do if it has access to too little memory. So if a feature you are trying to use isn't working, try setting a larger GPU memory split.
 
 Using `gpu_mem_256`, `gpu_mem_512`, and `gpu_mem_1024` allows you to swap the same SD card between 256MB, 512MB, and 1024MB Pis without having to edit `config.txt` each time:
 
@@ -22,6 +22,6 @@ The `gpu_mem_1024` command sets the GPU memory in megabytes for the 1024MB Raspb
 
 ### disable_l2cache
 
-Setting `disable_12cache` to `1` disables the CPU's access to the GPU's L2 cache. It requires a corresponding L2 disabled kernel. The default value is `0`.
+Setting this to `1` disables the CPU's access to the GPU's L2 cache, and requires a corresponding L2 disabled kernel. Default value is `0`.
 
 *This article uses content from the eLinux wiki page [RPiconfig](http://elinux.org/RPiconfig), which is shared under the [Creative Commons Attribution-ShareAlike 3.0 Unported license](http://creativecommons.org/licenses/by-sa/3.0/)*

hardware/display/README.md

@@ -2,17 +2,17 @@
 
 ## Introduction
 
-The Raspberry Pi display is an LCD display which connects to the Raspberry Pi through the DSI connector. It allows for the use of both the HDMI and LCD displays at the same time in some situations (this requires software support).
+The Raspberry Pi display is an LCD display which connects to the Raspberry Pi through the DSI connector. In some situations, it allows for the use of both the HDMI and LCD displays at the same time (this requires software support).
 
 ## Board Support
 
-The DSI display is designed to work with Raspberry Pi models that have mounting holes in a HAT footprint. Model A/B boards are supported, but require additional mounting hardware to fit the HAT-dimensioned stand offs on the display PCB.
+The DSI display is designed to work with Raspberry Pi models that have mounting holes in a HAT footprint. Model A/B boards are supported, but require additional mounting hardware to fit the HAT-dimensioned stand-offs on the display PCB.
 
 ### Attaching to Model A/B boards
 
-The DSI connector on the Model A/B boards does not have the I2C connections required to talk to the touchscreen controller and DSI controller. This can be worked around by using the additional set of jumper cables provided with the display kit to wire the I2C bus on the GPIO pins up to the display controller board.
+The DSI connector on the Model A/B boards does not have the I2C connections required to talk to the touchscreen controller and DSI controller. You can work around this by using the additional set of jumper cables provided with the display kit to wire up the I2C bus on the GPIO pins to the display controller board.
 
-Using the jumper cables, connect SCL/SDA on the GPIO header to the horizontal pins marked SCL/SDA on the display board. It is also recommended to power the Model A/B via the GPIO pins using the jumper cables.
+Using the jumper cables, connect SCL/SDA on the GPIO header to the horizontal pins marked SCL/SDA on the display board. We also recommend that you power the Model A/B via the GPIO pins using the jumper cables.
 
 For the GPIO header pinout, see [this diagram](http://pinout.xyz/).
 
@@ -22,7 +22,17 @@ DSI display autodetection is disabled by default on these boards. To enable dete
 
 Power the setup via the `PWR IN` micro-USB connector on the display board. Do not power the setup via the Pi's micro-USB port: the input polyfuse's maximum current rating will be exceeded as the display consumes approximately 400mA.
 
-NB: With the display connected to the GPIO I2C pins, the GPU will assume control of the respective I2C bus. The host operating system should not access this I2C bus as simultaneous use of the bus by both the GPU and Linux will result in sporadic crashes.
+NB: With the display connected to the GPIO I2C pins, the GPU will assume control of the respective I2C bus. The host operating system should not access this I2C bus, as simultaneous use of the bus by both the GPU and Linux will result in sporadic crashes.
+
+## Screen Orientation
+
+LCD displays have an optimum viewing angle, and depending on how the screen is mounted it may be necessary to change the orientation of the display to give the best results. By default, the Raspbery Pi display and Raspberry Pi are set up to work best when viewed from slightly above, for example on a desktop. If viewing from below, you can physically rotate the display, and then tell the system software to compensate by running the screen upside down.
+
+To flip the display, add, anywhere in the file `\boot\config.txt`, the following line:
+
+`lcd_rotate=2`
+
+This will vertically flip the LCD and the touch screen, compensating for the physical orientation of the display.
 
 ## Troubleshooting
 

hardware/raspberrypi/bootmodes/device.md

@@ -1 +1,16 @@
 # Device boot
+
+The following devices can boot through the special device boot mode:
+
+* Pi CM
+* Pi CM3
+* Pi Zero
+* Pi Zero W
+
+When this boot mode is activated (usually after a failure to boot from the SD card), it switches to a USB device and awaits a USB reset from the host. Example code showing how the host needs to talk to the Pi can be found [here](https://github.com/raspberrypi/usbboot).
+
+The host first sends a structure to the device down control endpoint 0. This contains the size and signature for the boot (security is not enabled so no signature is required). Secondly, code is transmitted down endpoint 1 (bootcode.bin).  Finally, the device will reply with a success code of:
+
+* 0    - Success
+* 0x80 - Failed
+

linux/usage/bashrc.md

@@ -1,8 +1,10 @@
 # .bashrc and .bash_aliases
 
-In your home folder, you will find a hidden file called `.bashrc` which contains some user configuration. You can edit this file to suit your needs.
+In your home folder you will find a hidden file called `.bashrc` which contains some user configuration options. You can edit this file to suit your needs. Changes made in this file will be actioned the next time a terminal is opened, since that is when the `.bashrc` file is read.
 
-Some useful adaptions are provided for you; some of these are commented out by default.
+If you want your changes to take place in your current terminal, you can use either `source ~/.bashrc` or `exec bash`. These actually do slightly different things: the former simply re-executes the `.bashrc` file, which may result in undesirable changes to things like the path, the latter replaces the current shell with a new bash shell, which resets the shell back to the state at login, throwing away any shell variables you may have set. Choose whichever is most appropriate.
+
+Some useful adaptions are provided for you; some of these are commented out with a `#` by default. To enable them, remove the `#` and they will be active next time you boot your Pi or start a new terminal.
 
 For example, some `ls` aliases:
 
@@ -28,9 +30,7 @@ More variations of `ls` are also provided:
 
 Ubuntu users may be familar with these as they are provided by default on that distribution. Uncomment these lines to have access to these aliases in future.
 
-The lines starting with a `#` are commented out. To enable them, remove the `#` and they will be active next time you boot your Pi.
-
-There is also reference to a `.bash_aliases` file which does not exist by default:
+`.bashrc` also contains a reference to a `.bash_aliases` file, which does not exist by default. You can add it to provide a handy way of keeping all your aliases in a separate file.
 
 ```
 if [ -f ~/.bash_aliases ]; then
@@ -46,4 +46,4 @@ Then you just create the file `.bash_aliases` and add more aliases like so:
 alias gs='git status'
 ```
 
-You can add other things directly to this file or to another, and include the file like the `.bash_aliases` example above.
+You can add other things directly to this file, or to another and include that file like the `.bash_aliases` example above.

remote-access/access-over-Internet/README.md

@@ -8,60 +8,11 @@ One method is to set up port forwarding on your router. To do this, you must cha
 
 ## Alternatives
 
-Alternative online services are available.
+Rather than using port forwarding, there are a number of alternative online services available. These provide varying levels of functionality - see their websites for more details.
 
-### remot3.it
+- [remot3.it](https://www.remot3.it), by Weaved Inc
+- [Dataplicity](https://dataplicity.com)
+- [Yaler.net](https://yaler.net/)
+- [Losant](https://losant.com)
+- [Remote IoT](https://remote-iot.com)
 
-One secure alternative to port forwarding is [remot3.it](https://www.remot3.it), by Weaved, Inc. remot3.it ("remote it") is software you install on your Raspberry Pi to access a single Pi, or manage a large number of Pis, from anywhere over the internet. Use remot3.it to access any TCP port on your Pi over the web including SSH, VNC, HTTP(S), RDP, and custom TCP services.
-
-From the command line on your Pi, update your Raspbian package lists:
-
-```bash
-sudo apt-get update
-```
-
-Install the remot3.it package:
-
-```bash
-sudo apt-get install weavedconnectd
-```
-
-Next, run the remot3.it installer with this command:
-
-```bash
-sudo weavedinstaller
-```
-
-The remot3.it installer will first ask you to create a user account by entering an email address and a password. Follow the on-screen menus to give your Pi a device name and choose what TCP ports/services to enable.
-
-Now access your Pi over the internet by signing in to www.remot3.it.
-
-For more detailed instructions and examples, see [Getting Started with remot3.it for Pi](http://forum.weaved.com/t/how-to-get-started-with-remot3-it-for-pi/1029).
-
-### Dataplicity
-
-[Dataplicity](https://dataplicity.com) allows you to connect and control your Pi's shell remotely from a web browser and its mobile apps. You can use Dataplicity's Wormhole feature to host a website or API directly from your Pi, and automatically enable HTTPS/SSL with no configuration or certificates.
-
-It uses WebSockets over HTTPS to provide a connection, and requires a single-line install.
-
-Dataplicity provides free support by e-mail and in-app messenger.
-
-For more information, consult the [documentation](https://docs.dataplicity.com/).
-
-### Yaler.net
-
-[Yaler.net](https://yaler.net/) enables secure web, SSH, and VNC access to your Pi from anywhere.
-
-The open source (Simplified BSD) YalerTunnel daemon is written in portable C.
-
-To access your Pi remotely via the Yaler relay infrastructure, [get started here](https://yaler.net/raspberrypi).
-
-### Losant
-
-Losant is an easy-to-use developer platform designed to help you quickly and securely build connected applications. Losant provides powerful data collection, aggregation, and visualization.
-
-With [Losant](https://losant.com), you can easily control and listen to the Raspberry Pi's GPIO. Losant's drag-and-drop workflow editor allows you to trigger actions, notifications, and machine-to-machine communication without programming.
-
-For detailed instructions, check out this [guide](https://www.losant.com/blog/how-to-access-your-raspberry-pis-gpio-over-the-internet).
-
-Losant uses open communication standards like REST and MQTT to provide connectivity to devices.