{"id":1776,"date":"2014-01-29T09:45:43","date_gmt":"2014-01-29T09:45:43","guid":{"rendered":"http:\/\/warc.org.uk\/?page_id=1776"},"modified":"2015-01-28T15:27:35","modified_gmt":"2015-01-28T15:27:35","slug":"1776-2","status":"publish","type":"page","link":"https:\/\/warc.org.uk\/?page_id=1776","title":{"rendered":"More on the Pi"},"content":{"rendered":"
General Purpose Input\/Output<\/h5>\n

 <\/p>\n

The Pi board has a 26 pin expansion header with 17 GPIO pins as well as +3.3V, +5V and GND supply lines.<\/p>\n

The default configuration provides 15 GPIO pins and a UART.<\/p>\n

The operating system also supports predefined alternate functions for some of the pins<\/p>\n

I\u00b2C (Integrated Circuit) is a two wire communication bus developed by Philips, for chip to chip communication.\u00a0 Commonly used for connecting sensors and port expanders.<\/p>\n

Serial Peripheral Interface (SPI) bus a synchronous serial data bus designed by Motorola.\u00a0 Commonly used in high speed applications such as digital audio, digital signal processing (DSP) and telecoms.<\/p>\n

UART, TXD and RXD.<\/p>\n

A Pulse Width Modulator (PWM).<\/p>\n

The OS makes the hardware available to a variety of high level program languages including Python, C, Java, BASIC, Perl and Bash shell scripts.<\/p>\n

Additional I\/O pins are available by hacking.<\/p>\n

 <\/p>\n

Serial Peripheral Interface<\/h5>\n

 <\/p>\n

\"spi\"<\/a><\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

Full duplex communication.<\/p>\n

Higher throughput than I\u00b2C.<\/p>\n

Complete protocol flexibility for the bits transferred.<\/p>\n

Not limited to 8-bit words.<\/p>\n

Arbitrary choice of message size, content, and purpose.<\/p>\n

Extremely simple hardware interfacing.<\/p>\n

Typically lower power requirements than I\u00b2C.<\/p>\n

No arbitration or associated failure modes.<\/p>\n

Slaves use the master’s clock, and don’t need precision oscillators.<\/p>\n

Slaves don’t need a unique address \u2014 unlike I\u00b2C.<\/p>\n

Transceivers are not needed.<\/p>\n

Uses only four pins on IC packages, and wires in board layouts or connectors, much fewer than parallel interfaces.<\/p>\n

At most one unique bus signal per device (chip select); all others are shared.<\/p>\n

Signals are unidirectional allowing for easy isolation.<\/p>\n

Not limited to any maximum clock speed, enabling potentially high throughput.<\/p>\n

 <\/p>\n

Now on to GPIO Pinout<\/a><\/p>\n

 <\/p>\n

The Raspberry Pi \u2013 An Introduction and more<\/a><\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

General Purpose Input\/Output   The Pi board has a 26 pin expansion header with 17 GPIO pins as well as +3.3V, +5V and GND supply lines. The default configuration provides 15 GPIO pins and a UART. The operating system also supports predefined alternate functions for some of the pins I\u00b2C\u2026<\/p>\n

Continue reading<\/i><\/a><\/p>\n","protected":false},"author":98,"featured_media":0,"parent":1762,"menu_order":0,"comment_status":"open","ping_status":"open","template":"templates\/template-page-with-intro.php","meta":{"footnotes":""},"class_list":["post-1776","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/warc.org.uk\/index.php?rest_route=\/wp\/v2\/pages\/1776","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/warc.org.uk\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/warc.org.uk\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/warc.org.uk\/index.php?rest_route=\/wp\/v2\/users\/98"}],"replies":[{"embeddable":true,"href":"https:\/\/warc.org.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1776"}],"version-history":[{"count":16,"href":"https:\/\/warc.org.uk\/index.php?rest_route=\/wp\/v2\/pages\/1776\/revisions"}],"predecessor-version":[{"id":70690,"href":"https:\/\/warc.org.uk\/index.php?rest_route=\/wp\/v2\/pages\/1776\/revisions\/70690"}],"up":[{"embeddable":true,"href":"https:\/\/warc.org.uk\/index.php?rest_route=\/wp\/v2\/pages\/1762"}],"wp:attachment":[{"href":"https:\/\/warc.org.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1776"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}