Hello guys !
I’m looking for a way to use a strip of 50 WS2801 leds with my beaglebone black. All the documents I’ve found are related to Arduino or Raspberry so I have some issues to know the path I should follow.
I have this driver : http://elinux.org/BeaconBoard so currently I’m trying to rebuild an Angstrom kernel with this.
If anyone has already done it or have any advice I’m eager to hear it !
Thanks !
Thanks !! I’ll try to adapt this to ws2801.
They should use the same communication “protocol” right ? Just SPI, but yeah I have no hands on there, but I’ve known the person who made that post for a while, so the information presented will be good.
I guess ! Maybe the timing is different, I’ll have to check the spreadsheet for that
I’ve just managed to make it work so I will give some feedback for those who would like to do the same.
Start with a fresh Angstrom kernel.
Disable HDMI :
Plug in the mini-usb cable from your board to your computer, open the Beaglebone partition and the uEnv.txt inside it.
Add this to the file : capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN- Boot the board. Run : cat /sys/devices/bone_capemgr.*/slots. You should see the two lines concerning the HDMI with P-O-- flags. There’s no L in this so it means it is disabled.
Follow the instructions to enable SPI : http://hipstercircuits.com/enable-spi-with-device-tree-on-beaglebone-black-copy-paste/ . You don’t need to try the bus yet, just make sure to download the python libraries he mentioned.
You have rebooted your board, if you run cat /sys/devices/bone_capemgr.*/slots you should see a line with BB-SPI1-01.
Download this to your BB : https://github.com/doceme/py-spidev
Run python setup.py install
In this repository : https://github.com/hackerspaceshop/RaspberryPI_WS2801_Bridge/tree/master/software. Download the LedStrip_WS2801.py file to your BB. You can use the demo.py to have an idea of what you can do with the library.
HW time : make sure your led strand is correctly powered (http://learn.adafruit.com/adalight-diy-ambient-tv-lighting/wiring-1 if you need help). Wire the led strand input to your BB : GND goes to pin 1 of P9, CO to pin 31 of P9, DO to pin 30 of P9.
Finally run python demo.py
Enjoy ! If it helped you, just let me know ; )
Thanks for the detailed instructions. It’s working for me with very little effort. In fact, if your are running the latest Debian image [1] the setup is even easier. py-spidev is already installed and you don’t have to disable the HDMI, rather you just disable a PWM.
beagle$ cat /sys/devices/bone_capemgr.*/slots
0: 54:PF—
1: 55:PF—
2: 56:PF—
3: 57:PF—
4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G
5: ff:P-O-L Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI
7: ff:P-O-L Override Board Name,00A0,Override Manuf,bspm_P9_42_27
8: ff:P-O-L Override Board Name,00A0,Override Manuf,bspm_P9_41_27
9: ff:P-O-L Override Board Name,00A0,Override Manuf,am33xx_pwm
10: ff:P-O-L Override Board Name,00A0,Override Manuf,bspwm_P9_21_b
Slot 10 is the PWM, so disable it with: beagle$ echo -10 > /sys/devices/bone_capemgr.*/slots
beagle$ cat /sys/devices/bone_capemgr.*/slots
0: 54:PF—
1: 55:PF—
2: 56:PF—
3: 57:PF—
4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G
5: ff:P-O-L Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI
7: ff:P-O-L Override Board Name,00A0,Override Manuf,bspm_P9_42_27
8: ff:P-O-L Override Board Name,00A0,Override Manuf,bspm_P9_41_27
9: ff:P-O-L Override Board Name,00A0,Override Manuf,am33xx_pwm
It’s gone, next enable SPI 0, beagle$ echo BB-SPIDEV0 > /sys/devices/bone_capemgr.*/slots
0: 54:PF—
1: 55:PF—
2: 56:PF—
3: 57:PF—
4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G
5: ff:P-O-L Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI
7: ff:P-O-L Override Board Name,00A0,Override Manuf,bspm_P9_42_27
8: ff:P-O-L Override Board Name,00A0,Override Manuf,bspm_P9_41_27
9: ff:P-O-L Override Board Name,00A0,Override Manuf,am33xx_pwm
11: ff:P-O-L Override Board Name,00A0,Override Manuf,BB-SPIDEV0
–Mark