RaspberryPi/LCD Display - Revision history

Admin at 19:00, 20 June 2016

2016-06-20T19:00:23Z

← Older revision		Revision as of 19:00, 20 June 2016
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	Also see [[Arduino LCD Display]]~~, which was the original~~.		Also see the original project, which was using an Arduino to control this LCD display: [[Arduino/LCD Display]]

			[[Image:LCD16pins_3.jpg\|400px]]

	=Overview=		=Overview=

Admin: /* The Result */

2016-06-15T07:15:13Z

The Result

← Older revision		Revision as of 07:15, 15 June 2016
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	==The Result==		==The Result==

	[[Image:Pi_LCD_1.jpg\|~~400px~~]]		[[Image:Pi_LCD_1.jpg\|500px]]

	[[Image:Pi_LCD_2.jpg\|~~400px~~]]		[[Image:Pi_LCD_2.jpg\|500px]]

	=Flags=		=Flags=

	{{PiFlag}}		{{PiFlag}}

Admin: /* Pinout */

2016-06-15T07:06:00Z

Pinout

← Older revision		Revision as of 07:06, 15 June 2016
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	==Preparing the Pi==		==Preparing the Pi==

	==Pinout==		===Pinout===

	See [https://howto8165.files.wordpress.com/2014/08/rpi-pinout.png] for Raspberry Pi pinout diagram.		See [https://howto8165.files.wordpress.com/2014/08/rpi-pinout.png] for Raspberry Pi pinout diagram.

Admin: /* The Code */

2016-06-15T07:04:20Z

The Code

← Older revision		Revision as of 07:04, 15 June 2016
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	See [[Arduino LCD Display#Overview]] for an overview of how the LCD display works. It works by communicating with the microcontroller using I2C pins, which provide a way for integrated circuits to communicate with each other.		See [[Arduino LCD Display#Overview]] for an overview of how the LCD display works. It works by communicating with the microcontroller using I2C pins, which provide a way for integrated circuits to communicate with each other.

	~~=The Code=~~

	~~This section covers the software needed to drive the LCD display via the GPIO pins on the Raspberry Pi.~~

	Adafruit provides an entire package for interfacing with character LCD displays [https://github.com/adafruit/Adafruit_Python_CharLCD]. Unfortunately, however, these are for LCDs that do not have an integrated circuit onboard, and so have a much greater number of pins. This is an excellent illustration of why we would want to install an integrated circuit to control the LCD, rather than controlling the LCD directly.		Adafruit provides an entire package for interfacing with character LCD displays [https://github.com/adafruit/Adafruit_Python_CharLCD]. Unfortunately, however, these are for LCDs that do not have an integrated circuit onboard, and so have a much greater number of pins. This is an excellent illustration of why we would want to install an integrated circuit to control the LCD, rather than controlling the LCD directly.
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	[[Image:LCD16pins_3.jpg\|400px]]		[[Image:LCD16pins_3.jpg\|400px]]

			=The Code=

			This section covers the software needed to drive the LCD display via the GPIO pins on the Raspberry Pi.

	==Preparing the Pi==		==Preparing the Pi==

Admin: /* The Code */

2016-06-15T07:01:19Z

The Code

← Older revision		Revision as of 07:01, 15 June 2016
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	==Preparing the Pi==		==Preparing the Pi==

			==Pinout==

			See [https://howto8165.files.wordpress.com/2014/08/rpi-pinout.png] for Raspberry Pi pinout diagram.

			To run a simple hello world with the Sainsmart LCD hooked up to the Pi, it is necessary to send IC2 signals out over pins 3 and 5, SDA/SCL.

	===Basic Connection to Pi===		===Basic Connection to Pi===
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	$ sudo chown `id -u`.`id -g` /dev/spidev0.*		$ sudo chown `id -u`.`id -g` /dev/spidev0.*
	</pre>		</pre>

	~~==Hello World==~~

	~~See [https://howto8165.files.wordpress.com/2014/08/rpi-pinout.png] for Raspberry Pi pinout diagram.~~

	~~To run a simple hello world with the Sainsmart LCD hooked up to the Pi, it is necessary to send IC2 signals out over pins 3 and 5, SDA/SCL.~~

	===SMBus===		===SMBus===

Admin: Admin moved page Raspberry Pi LCD Display to RaspberryPi/LCD Display

2016-06-15T06:56:19Z

Admin moved page Raspberry Pi LCD Display to RaspberryPi/LCD Display

← Older revision	Revision as of 06:56, 15 June 2016
(No difference)

Admin: /* The Circuit */

2016-06-15T06:27:40Z

The Circuit

← Older revision		Revision as of 06:27, 15 June 2016
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	* SCL - connects the SCL port on the LCD display to the SCL port of the Raspberry Pi GPIO pins		* SCL - connects the SCL port on the LCD display to the SCL port of the Raspberry Pi GPIO pins

	There ~~is some yadda yadda about~~ 3.3 V vs 5 V. ~~Hope that~~ it ~~doesn't matter!~~		There should be an additional circuit between the 3.3 V Pi and the 5 V LCD, but (apparently) it is not necessary. I hope it is not necessary.

	==The Result==		==The Result==

Admin: /* The Code */

2016-06-15T06:26:39Z

The Code

@@ Line 30: / Line 30: @@
 * Give the Pi a minute to finish booting up, then connect it using an Ethernet cable to your desktop/computer
 * Remotely log in to the Pi via SSH
 ===Enable SPI===
@@ Line 114: / Line 82: @@
 To run a simple hello world with the Sainsmart LCD hooked up to the Pi, it is necessary to send IC2 signals out over pins 3 and 5, SDA/SCL.
 ===SMBus===
@@ Line 124: / Line 89: @@
 To communicate over the I2C ports, you can use the I2C standard protocol, but you can also use SMBus, which is a subset of the I2C protocol. SMBus is common in devices, I suppose, so you want to use it when you can - that way, it'll work if I2C is used, and it'll work if SMBus is used.
-Unfortunately, however, before we can use this code, we need to address the fact that the Pi uses 3.3 V logic, but the LCD display uses 5.5 V logic. So we need a logic converter, 3.3V to 5V.
+Before we can use this code, we need to address the fact that the Pi uses 3.3 V logic, but the LCD display uses 5.5 V logic. So we need a logic converter, 3.3V to 5V. Apparently, this is necessary. But it actually works without it. Not sure why.
 ===Aptitude===
 <pre>
 sudo apt-get install python-smbus i2c-tools
 </pre>
 =The Circuit=

Admin: /* Other Code */

2016-06-15T06:20:59Z

Other Code

← Older revision		Revision as of 06:20, 15 June 2016
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	sudo apt-get install python-smbus i2c-tools		sudo apt-get install python-smbus i2c-tools
	</pre>		</pre>

	~~===Other Code===~~

	~~This advertises itself as a drop-in for smbus: https://github.com/adafruit/Adafruit_Python_PureIO~~

	=The Circuit=		=The Circuit=

Admin: /* If only we had aptitude */

2016-06-15T06:20:45Z

If only we had aptitude

← Older revision		Revision as of 06:20, 15 June 2016
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	Unfortunately, however, before we can use this code, we need to address the fact that the Pi uses 3.3 V logic, but the LCD display uses 5.5 V logic. So we need a logic converter, 3.3V to 5V.		Unfortunately, however, before we can use this code, we need to address the fact that the Pi uses 3.3 V logic, but the LCD display uses 5.5 V logic. So we need a logic converter, 3.3V to 5V.

	===~~If only we had aptitude~~===		===Aptitude===

	<pre>		<pre>
	sudo apt-get install python-smbus i2c-tools~~. Enter "sudo reboot" to restart the pi and now the I2C pins will be available to use.~~		sudo apt-get install python-smbus i2c-tools
	</pre>		</pre>