RPi 硬件基础设置

= 你需要拥有的典型硬件 = You may have decided to buy a Raspberry Pi because you think it is great, it helps if you have an idea of what you want to do with it. You buy the board, but you will need some extra parts to be able to use it. Some of those parts you may have around so you can use them, some you might buy that others have given away or sold, and some you buy yourself. Consider what you buy; you might get very little benefit from an expensive item over a cheap one.

The Raspberry Pi can be used in the conventional computer configuration, with a keyboard, mouse and display, or in a "headless" configuration where it is available on a network and is controlled from another computer on that network. You can add a range of additional peripherals to the Pi; the first section of this page covers setting up the Pi with the minimum number of peripherals to make sure that you can get it working. Additional peripherals are covered in the second section.

IMPORTANT For USB devices other than a mouse and a simple wired keyboard (for USB devices drawing more than 100mA) a powered USB hub is strongly recommended. A technical discussion as to why can be found here. Specifically the RPi's built in USB hub is designed only for "Single current unit" USB devices. Note that when using Revision 2 (or later) boards the problem has been mitigated somewhat with the removal of the USB polyfuses, still due to the limited current the PI can provide to USB devices, due to its main polyfuse, its still recommended to use a hub for all USB peripherals requiring more than 100mA.

Other, optional equipment includes:


 * Case
 * SD card reader - if you need to prepare your own SD card
 * Power Supply Switch - if you want an easy way to cycle power

Power Supply
The unit uses a Micro USB connection to power itself (only the power pins are connected - so it will not transfer data over this connection). A standard modern phone charger with a micro-USB connector will do, but needs to produce at least 700mA at 5 volts. Check your power supply's ratings carefully, and beware cheap knock-offs!.

The Pi Hut offers a 5V 1500mA power supply, manufactured specially for the Raspberry Pi. This is available in three varieties :
 * UK
 * EU
 * USA

Other suitable mains adapters will be available from the RPi Shop, as well as eBay. ModMyPi's Raspberry Pi Shop stocks a 5V 2A bespoke charger designed specifically for use with the Raspberry Pi.

You can use a range of other power sources (assuming they are able to provide enough current ~700mA):
 * Computer USB Port or powered USB hub (will depend on power output)
 * Special wall warts with USB ports
 * Mobile Phone Backup Battery (will depend on power output) (in theory - needs confirmation)
 * Modern TV with built-in USB (for example, it has been shown to work with the Sony KDL-40HX723 and KDL-55NX813)
 * Internet Routers with USB Ports (the BT Home Hub 3 seems to run the Pi nicely)

To use the above, you'll need a USB A 'male' to USB micro 'male' cable - these are often shipped as data cables with mobile phones.

Power Switch
Additionally, the Raspberry Pi does not have the functionality of an on/off switch like traditionally seen on a PC. Pi Supply have for sale an add on board that introduces this functionality, allowing you to easily manage power on your Raspberry Pi, without wearing out your back, or the micro-USB socket on the Pi. It also includes a safe shutdown switch to avoid corruption of your SD card.

For detailed information about power requirements see RPi Hardware - Power.

Portable Battery Pack
Want to use your Raspberry Pi on the go? Then you need a Portable Power Pack! The rechargeable battery pack allows you to use your Raspberry Pi anywhere. Available from The Pi Hut - Portable Power Pack for the Raspberry Pi

Prepared Operating System SD Card
The RPi has no internal storage or built-in boot code, so it requires an SD-Card that is set up to boot the RPi and launch the Operating System. You should look at the RPi Easy SD Card Setup page for instructions about buying a preinstalled card or creating your own loaded SD Card.

Keyboard & Mouse
Most standard USB keyboards and mice will work with the RPi. Wireless keyboard/mice should also function, and only require a single USB port for an RF dongle. In order to use a Bluetooth keyboard or mouse you would need to use a Bluetooth dongle, which again uses a single port.

Remember that the Model A has a single USB port and the Model B only has two (typically a keyboard and mouse will use a USB port each) - see USB Hub below.

To check your mouse and keyboard are compatible with Linux, see RPi Verified Peripherals.

Display
There are two connection options for the RPi display, HDMI (high definition) and Composite (low definition).


 * HD TVs and most LCD Monitors can be connected using a full-size 'male' HDMI cable, and with an inexpensive adaptor if DVI is used. HDMI versions 1.3 and 1.4 are supported, and a version 1.4 cable is recommended. The RPi outputs audio and video via HMDI, but does not support HDMI input.


 * Most older TVs can be connected using Composite (a yellow-to-yellow cable). PAL and NTSC TVs are supported. Note that the RCA output is composite video, not RF, so it cannot be connected directly to the antenna input of a TV, you need to connected it the the yellow video input connector, or to the SCART input using a RCA to SCART plug, (adapter).

When using composite video, audio is available from a 3.5mm (1/8 inch) socket, and can be sent to your TV, or to an amplifier. To send audio to your TV, you will need a cable which adapts from 3.5mm to double (red and white) RCA connectors. These red and white can go into the red and white RCA plug inputs of a TV, or a stereo set, or to the above mentioned RCA to SCART plug. Another option for audio (when not using HDMI) is to connect the 3.5mm jackplug to an amplified speakerset. Do not connect the 3.5 mm jack directly to a headset, as the 3.5 mm audio output isn't suitable to drive headsets, only amplifier inputs. Attaching a low impedance load, (such as a headset) to the stereo audio output may lead to distorted sound.

Using an HDMI to DVI-D (digital) adaptor plus a DVI to VGA adaptor will not work. HDMI does not supply the DVI-A (analogue) needed to convert to VGA - converting an HDMI or DVI-D source to VGA (or component) needs an active converter. (It can work out cheaper to buy a new monitor). Problems have been reported with converters if the power supply is not adequate and the converter is not powered from its own power supply.

The Pi Hut offer two adapters that will allow the Raspberry Pi to be used with multiple monitor formats
 * Standard HDMI
 * VGA adapter
 * DVI adapter

For detailed information see Rpi Screens.

Cables
You will probably need a number of cables in order to connect your RPi up.
 * 1) Micro-B USB Power Cable (see above) picture. This has to be a high quality one.
 * 2) HDMI-A picture or Composite cable picture, plus DVI adaptor picture or SCART adaptor picture if required, to connect your RPi to the Display/Monitor/TV of your choice.
 * 3) Audio cable picture, this is not needed if you use a HDMI TV/monitor.
 * 4) Ethernet/LAN Cable (see below) picture.

The price you pay for an HDMI cable can very wildly and under most circumstances a low-cost cable from a reputable online or local supplier will be absolutely fine, but the definition of what constitutes 'low cost' can vary wildly - for example, in the UK, a 1m cable can be purchased for anything between £1 and £24.99. If, however, you want to drive a display some distance from the RPi (say greater than the ubiquitous 1.8m/6ft), or you are using a video switch to share a display between several devices, then higher quality cables might be wise - for example, a pair of 1m HDMI cables purchased in a UK 'pound shop' worked fine when directly connected between the RPi and a display, but would not give a stable picture when used via an HDMI switch. Replacing the £1 1m cable with a 1.5m cable bought online for £1.30 fixed the problem. For more insight: Why you don't need to spend more than £2 on an HDMI cable

Fully tested cables are available from Pi Supply, The Pi Hut's Raspberry Pi Store, and ModMyPi's Raspberry Pi Shop offers a range of High Quality coloured 'Noodle' cables.

Network / Internet Connectivity
This may be an Ethernet/LAN cable (standard RJ45 connector) or a USB WiFi adaptor. The RPi ethernet port is auto-sensing which means that it may be connected to a router or directly to another computer (without the need for a crossover cable ).

Support for USB WiFi adaptors will vary - see RPi Verified Peripherals.

Note: If a Netgear router has a blank in the fourth box of the subnet mask, raspbian will interpret that as a 255, not as a '0' like Ubuntu. This will give you a subnet mask of 255.255.255.255 and a useless network connection. Changing the router's setting to put a '0' in the last field and reinitializing the network will fix this.

USB-Hub
In order to connect additional devices to the RPi, you may want to obtain a USB Hub, which will allow multiple devices to be used.

It is recommended that a powered hub is used - this will provide any additional power to the devices without affecting the RPi itself. The USB ports are fused at about 140ma each without an additional external power source. This not enough to power a hard drive, and you may even have trouble powering wireless adapters and other peripherals. There is enough current out there, however, for mice and most keyboards. (see RPi Hardware - Power section).

USB version 2.0 is recommended. USB version 1.1 is fine for keyboards and mice, but may not be fast enough for other accessories.

Real Time Clock
Laptops and computers keep time when the power is off by using a pre-installed, battery powered 'Real Time Clock' (RTC). However, this Real Time Clock module is not included with the Raspberry Pi. To keep time, the Raspberry Pi updates the date and time automatically over the internet via Ethernet or WiFi. For projects which have no internet connection, you may want to add a low cost battery powered RTC to help your Pi keep time!

Afterthought Software have released a 'Plug and Play' Real Time Clock designed specifically for the Raspberry Pi which, unlike other RTC's available, plugs directly in to the Raspberry Pi's GPIO Ports. The unit is available from ModMyPi and comes complete with an easy to follow Installation Guide.

Another PC
If you need to install the Operating System on your own SD Card you will need another PC, Laptop or Mac to do so (or get a friend or local group to do it for you). If you are running headless, you also need one, though for a lot of uses (but not all) you can use a tablet or smart phone. This does include another Pi!

= Connecting Together =

You can use the diagram to connect everything together using the following instructions:


 * 1) Plug the SD Card loaded with the Operating System into the Pi.
 * 2) If required, plug the USB keyboard and mouse into the Pi, perhaps via a USB Hub. Connect the Hub to power, if necessary.
 * 3) If required, plug the video cable into the display and into the Pi.
 * 4) Plug in your Network cable, or WiFi dongle, if required.
 * 5) Ensure that your USB Hub (if any) and display are working.
 * 6) With your screen on, plug the other end of the power source into the Pi.
 * 7) Plug the power source into the main socket, and switch it on.
 * 8) If connected to a display, the Pi should boot up and display messages on the screen.
 * 9) If running headless, it should boot up. When the leds have stopped flashing, connect to the Pi from the remote computer. Whether this works will depend on the operating system you are using; the Raspian Linux operating system is configured to allow SSH connections by default.

It is always recommended to connect the MicroUSB Power to the unit last (while most connections can be made live, it is best practice to connect items such as displays and other connections with the power turned off).

If you use both a R-PI power supply and a powered hub, its recommended you connect them to the same switched power bar, and use the switch on the power bar to switch off both the R-PI and hub at the exact same time.

Also, always shutdown using the software shutdown function, not by pulling the plug. When not using a GUI, (with a GUI use the GUI command) you can use the command "sudo halt", and power off when all the LED's on the board (except the power LED) go off. This is especially important the first time you boot, as in the process the R-PI modifies the content of the SD-card, without a clean shutdown the contents of the card may be damaged.

The RPi may take a long time to boot when powered-on for the first time, so be patient, and cleanly shutdown afterwards, as described above!

= Additional Peripherals = You may decide you want to use various other devices with your RPi, such as Flash Drives/Portable Hard Drives, Speakers etc.

For detailed information see RPi Verified Peripherals.

Heatsink
Not a vital accessory for your RPi, but will help to reduce the CPU's temperature whilst under load. Available from The Pi Hut's Raspberry Pi Store, Etsy, ModMyPi (with lots of tips and tricks for reducing temperature in the reviews) or eBay

Case
Since the RPi is supplied without a case, it will be important to ensure that you do not use it in places where it will come into contact with conductive metal or liquids, unless suitably protected. Some form of case should be considered, and there is a Rpi case thread on the forum. Cases are also available from The Pi Hut's Raspberry Pi Store,ModMyPi's Raspberry Pi Shop and MobileApp Systems.

For detailed information see Rpi Cases.

SD card reader
You may need an SD card reader to prepare an SD card, or read a second one, both for the Pi or the other computer if it does not have an integral SD card reader.

ModMyPi's Raspberry Pi Shop stocks a low cost (99p) SD Card Reader.

Expansion & Low Level Peripherals
If you plan on making use of the low level interfaces available on the RPi, then ensure you have suitable header pins for the GPIO (and if required JTAG) suitable for your needs.

Also if you have a particular low-level project in mind, then ensure you design in suitable protection circuits to keep your RPi safe (details will be made available within the RPi Projects, Guides & Tutorials section).

For detailed information see Rpi Low-level Peripherals.

= External Links =

For a verbose guide aimed at absolute beginners, see Peripherals You'll Need and Getting Started in h2g2's 'Introducing the Raspberry Pi'.

For a cautionary tale of '7 gotchas' to be on the lookout for (especially concerning the re-use of old monitors, keyboards, etc), see Raspbery Pi 'Gotchas' and new buyer tips

= References =