Raspberry Pi Serial - Revision history

Cartridge1987: /* getting SPI and I2C drivers to work on raspian */

2015-11-11T11:11:26Z

getting SPI and I2C drivers to work on raspian

2015-11-11T11:11:13Z

signal levels

2015-11-02T11:34:18Z

2015-11-02T11:32:14Z

2014-08-14T14:11:03Z

Possible Configurations

2012-10-31T15:55:27Z

Pinout

2012-08-14T07:24:59Z

Programming

2012-08-12T11:46:36Z

Programming

2012-06-01T15:31:22Z

Possible Configurations

2012-06-01T15:28:47Z

Possible Configurations

@@ Line 58: / Line 58: @@
 Now, you can use the tools in either the SPI or I2C subdirectory to communicate with bitwizard SPI or I2C boards that you might have.
-== getting SPI and I2C drivers to work on raspian ==
+== Getting SPI and I2C drivers to work on raspian ==
  sudo wget https://raw.github.com/Hexxeh/rpi-update/master/rpi-update -O /usr/bin/rpi-update
@@ Line 71: / Line 71: @@
-=== changelog ===
+=== Changelog ===
 * Initial public release

@@ Line 21: / Line 21: @@
 If you remove the solder jumper and forget to put it back on in the other position (or if you fail to make the contact), the power led will not light.
-=== signal levels ===
+=== Signal levels ===
 Many expansion boards that you might want to connect to your raspberry pi will be 5V, whereas the Raspberry Pi works at 3.3V. To convert the signal levels you need a level shifter.

@@ Line 5: / Line 5: @@
 The RPI_SERIAL board breaks out the serial busses on the raspberry pi. This allows the raspberry pi to communicate at 3.3V CMOS levels with say an arduino mini or other 3.3V asynchronous devices. But also the I2C bus and SPI busses are broken out. BitWizard has a bunch of expansion boards that can connect to those busses.
-You can buy the Raspberry Pi Serial board in the [http://www.bitwizard.nl/shop/breakout-boards/serial-bob BitWizard shop].
+You can find the Raspberry Pi Serial board in the [http://www.bitwizard.nl/shop/index.php?route=product/search&search=Bob BitWizard shop].
 This page will say more about the hardware in the future, once things are tested. For now see [[Raspberry pi expansion system page]]

@@ Line 5: / Line 5: @@
 The RPI_SERIAL board breaks out the serial busses on the raspberry pi. This allows the raspberry pi to communicate at 3.3V CMOS levels with say an arduino mini or other 3.3V asynchronous devices. But also the I2C bus and SPI busses are broken out. BitWizard has a bunch of expansion boards that can connect to those busses.
+You can buy the Raspberry Pi Serial board in the [http://www.bitwizard.nl/shop/breakout-boards/serial-bob BitWizard shop].
 This page will say more about the hardware in the future, once things are tested. For now see [[Raspberry pi expansion system page]]

@@ Line 19: / Line 19: @@
 If you remove the solder jumper and forget to put it back on in the other position (or if you fail to make the contact), the power led will not light.
+=== signal levels ===
+Many expansion boards that you might want to connect to your raspberry pi will be 5V, whereas the Raspberry Pi works at 3.3V. To convert the signal levels you need a level shifter.
+For I2C  the board implements a level shifter as recommended by Philips (inventor of I2C).
+For SPI and UART the 3.3V signals coming out of the Raspberry Pi are sufficiently high that all 5V devices that we could find recognized the signal as high. For the 5V signals going to the Raspberry Pi, we have limited the voltage to just above 3.3V by putting a scottky diode from the signal to the 3.3V, as well as a 1k resistor to limit the current. This sufficiently protects the raspberry pi from damage by the 5V signals from 5V devices.
+Some care should be taken: The 5V device should NOT drive the signals that are normally driven by the raspberry pi. Normally you'd have two outputs driving against eachother, now there is also the 5V vs 3.3V issue....
 == Pinout ==

@@ Line 22: / Line 22: @@
 == Pinout ==
-The 28 pin gpio connector is described at elinux: [[http://elinux.org/RPi_Low-level_peripherals]]
+The 26 pin gpio connector is described at elinux: [[http://elinux.org/RPi_Low-level_peripherals]]
 The SPI connector has the same pinout as the atmel 6-pin ICSP connector and is documented here: [[SPI_connector_pinout]].

@@ Line 41: / Line 41: @@
-New: get bw_rpi_tools . XXX figure out where they are.
+New: get bw_rpi_tools .
+   git clone https://github.com/rewolff/bw_rpi_tools.git
-You can send things from your 'pi to the I2C and SPI busses using the tools from:
+Now, you can use the tools in either the SPI or I2C subdirectory to communicate with bitwizard SPI or I2C boards that you might have.
-http://www.bitwizard.nl/software/gpio_spi_i2c_20120419.tgz
 == getting SPI and I2C drivers to work on raspian ==

@@ Line 39: / Line 39: @@
 == Programming ==
+New: get bw_rpi_tools . XXX figure out where they are.
 You can send things from your 'pi to the I2C and SPI busses using the tools from:
@@ Line 44: / Line 47: @@
 http://www.bitwizard.nl/software/gpio_spi_i2c_20120419.tgz
+== getting SPI and I2C drivers to work on raspian ==
-Work is still underway to make a kernel-level driver for I2C and SPI.
+ sudo wget https://raw.github.com/Hexxeh/rpi-update/master/rpi-update -O /usr/bin/rpi-update
+ sudo chmod +x /usr/bin/rpi-update
+ sudo rpi-update
+will install the latest kernels with spidev support. Next comment out the two blacklist lines in /etc/modprobe.d/raspi-blacklist.conf:
+ sudo mv /etc/modprobe.d/raspi-blacklist.conf /etc/modprobe.d/raspi-blacklist.conf.orig
+ sudo sed -e 's/^b/#b/' /etc/modprobe.d/raspi-blacklist.conf.orig > /etc/modprobe.d/raspi-blacklist.conf
+(you could do this with your favorite editor, but this way you can just cut-paste these lines and get it done....)

@@ Line 16: / Line 16: @@
 The board can be configured for EITHER 3.3V or 5V. This is done by moving a solder-jumper. See [[solder jumpers]] for how to move a solder jumper.
-In contrast to the expansion boards that have a "default" setting for the solder jumper by having a small trace between two of the pads, the RPI_SERIAL boards have been designed to FORCE us to think about what option we want by not providing any default. So far most boards have been soldered for 5V prior to being shipped. Unless someone convinces us otherwise, this will probably remain like this.
+In contrast to the expansion boards that have a "default" setting for the solder jumper by having a small trace between two of the pads, the RPI_SERIAL boards have been designed to FORCE us to think about what option we want by not providing any default. So far most rpi_serial boards have been soldered for 5V prior to being shipped. Unless someone convinces us otherwise, this will probably remain like this.
 If you remove the solder jumper and forget to put it back on in the other position (or if you fail to make the contact), the power led will not light.