Bw tool - Revision history

Rew: /* Basic Example */

2023-12-05T09:50:39Z

Basic Example

2023-12-05T09:49:25Z

Setting up I2C/SPI under Linux

2015-10-21T12:25:10Z

Sending Data

2015-10-21T12:14:34Z

Options Specifying the Device

2015-10-21T12:12:33Z

Options Specifying the Device

2015-09-03T15:21:59Z

Options Specifying the Device

2015-09-03T15:19:01Z

Basic Example

2015-09-03T15:17:16Z

Installation/Compiling

2014-08-20T14:03:22Z

Setting up I2C/SPI under Linux

2014-07-21T13:28:10Z

@@ Line 44: / Line 44: @@
 If you have a rpi_ui plugged onto your raspberry pi, add:
  -a 94
+So the complete commandline would become:
+ bw_tool -D /dev/i2c-1 -I -a 94 -t "Hello world!"
 = About Permissions =

@@ Line 14: / Line 14: @@
 == Setting up I2C/SPI under Linux ==
+The modern way is to do it with raspi-config. Enter raspi-config, select "interface options", select I2C or SPI depending on what you need, and turn it on. After changing this just now, I did not need to reboot to make the setting active.
+Below is what raspi-config does behind the scenes, probably updated for later versions of the kernel and the raspberry pi.
 On Raspberry pi, raspbian, you first need to edit /boot/config.txt . Near the bottom you will find a line that reads:

@@ Line 102: / Line 102: @@
 The option
- -W <addr>:<short>
+ -W <addr>:<data>:<type>
-will write the 16-bit short to the port at addr. For example -W 81:1000 will write the value 0x1000 to the numsamples port on an analog-equipped board.
+will write the data to the port at addr, using the datasize specified in "type": b for byte, s for short (16 bits), i for integer (32 bits) and l for long (64 bits) . For example -W 81:1000:s will write the value 0x1000 to the numsamples port on an analog-equipped board.
 == Reading Data ==

@@ Line 83: / Line 83: @@
 The option
  -S
-will scan the bus for bitwizard protocol devices. This only works for SPI devices.
+will scan the bus for bitwizard protocol devices. This only works for SPI devices. Use the i2cdetect command (in the package i2ctools) to scan the I2C bus if you have i2c devices.
 == Identifying the Device ==

@@ Line 80: / Line 80: @@
  -a <address>
 specifies the address of the device to use. Note that BitWizard uses the full 8 bits that are sent to the device. Add one for "read" operation. In some circles, notably I2C, it is customary to specify just those 7 bits. Thus when the I2C_LCD is at the default address of 0x82, i2cdetect will scan it at address 0x41.
+The option
+ -S
+will scan the bus for bitwizard protocol devices. This only works for SPI devices.
 == Identifying the Device ==

@@ Line 33: / Line 33: @@
 will display the shown text on an SPI_LCD on the default SPI bus (SPI0). Options modify the defaults.
+For example, if you have an I2C module, add:
+ -I -D /dev/i2c-1
+to switch to i2c-mode and specify the correct device.
+If you have a rpi_ui plugged onto your raspberry pi, add:
+ -a 94
 = About Permissions =

@@ Line 9: / Line 9: @@
 Nowadays the "bw_tool" is the only directory of interest. Go there and build:
- ''cd bw_tool; make''
+ ''cd bw_rpi_tools/bw_tool; make''
-should work fine. If things went smoothly (which they usually do) you can install the binary so that normal people can find it:
+should work fine. If things went smoothly (which they usually do) you can install the binary so that normal users on your rpi can find it:
   ''make install''
 == Setting up I2C/SPI under Linux ==
-To get Linux to work with SPI/I2C the proper modules need to be loaded. To do this automatically on boot:
+On Raspberry pi, raspbian, you first need to edit /boot/config.txt . Near the bottom you will find a line that reads:
-'''0''': (on Raspberry Pi) edit /etc/modprobe.d/raspi-blacklist.conf to look like this:
+ #dtparam=i2c_arm=on
- # blacklist spi and i2c by default (many users don't need them)
+You need to remove the hashmark so that it becomes:
- #blacklist spi-bcm2708
+ dtparam=i2c_arm=on
- #blacklist i2c-bcm2708
-'''1''': Add the following lines to /etc/modules:
+To activate this a reboot is required.
- i2c-dev
- spidev
+Then you need to make sure that the i2c-dev module is loaded. For testing, type:
-'''2''': Reboot
+ modprobe i2c-dev
+but to make it permantently add "i2c-dev" to /etc/modules .
 = Basic Example =