Beaglebone Black Wireless GHI

I suppose I can ask here?

I have ordered a Beaglebone Black Wireless GHI ( Mouser part number 958-BBBWL-SC-562 )

It is my understanding that the Beaglebone is fussy about what LCD is used.
Somewhere I read, some LCd’s can burn out the board ???

Does GHI have any recommendations about what LCD I should use?

I found http://www.mouser.com/new/4d-systems/4Dsystems-LCDcape-BeagleBoneBlack/
Would these be OK?

Thank You.

Where did you see such info?.All I knew is that not all pins are free on the seeed version but pins on the black and black wireless are the same.

@ Gus -

I believe my question is based on the text found here. (I think it was at this link)
http://elinux.org/CircuitCo:BeagleBone_LCD7

BeagleBone LCD7 Cape revision A2 Compatible with BeagleBone using Angstrom release 06-18-12 onward.
Compatible with BeagleBone Black using Angstrom release 2013-06-20 onward. However, only booting from SD card is supported. Note: Using Angstrom release earlier than 2013-06-20 on BeagleBone Black and LCD7 may DAMAGE your BeagleBone Black. Ensure you are using 2013-06-20 or later.

I ask because I know little about Beaglebone problems.
So I ask the experts!

Thanks

Interesting, this needs to be looked into.

@ willgeorge -

The 4D Systems LCD cape will work just fine. I have a couple of these and really like them.

The source of the concern is that BeagleBone Black provides access to the same signals on the cape header pins as the original BeagleBone, but it utilizes some of the pin resources for local interfaces, namely some LCD (LCD_) and I2S (SPI1_) signals are utilized by the on-board HDMI transmitter and some MMC (MMC1_*) signals are utilized by the on-board eMMC.

When using an add-on LCD, the LCD and I2S outputs from BeagleBone to the HDMI framer don’t matter because we no longer care about the output of that HDMI framer. They can also easily be converted to other modes by disabling the HDMI at boot-up by modifying the /boot/uEnv.txt configuration file. That file provides information to the bootloader that gets passed to the kernel to disable the HDMI framer and avoid consuming those pins.

The real signals of concern are the ones driven by the on-board eMMC. Some capes older than BeagleBone Black might have chosen to utilize those pins in their design. In the case that the add-on cape and on-board eMMC drive those signals at the same time, you can possibly damage the eMMC or processor.

The work-around is to boot from a microSD card and disable the eMMC using the image on that microSD card. This is also done using the /boot/uEnv.txt configuration file stored on the microSD card.

You can see a big of this illustrated on the following page and in the attached image:
http://beagleboard.org/Support/bone101#headers

Again, the good news is that the 4D Systems LCD cape was designed after BeagleBone Black and comprehends the utilization of the MMC1 pins by the on-board eMMC.

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@ jkridner - Thanks and welcome to the community.

@ Gus -

Happy to be here. By the way, regarding the differences between the cape header usage of BeagleBone Black, BeagleBone Black Wireless and SeeedStudio BeagleBone Green Wireless…

BeagleBone Black and BeagleBone Black Wireless utilize the same cape header pins for on-board HDMI and eMMC. All the WiFi/Bluetooth pins were taken from the 10/100 Ethernet pins.

SeeedStudio BeagleBone Green Wireless, as of rev 1.1 schematic, additionally utilizes on-board:
P8_12 for MMC2_DAT0 (WL SDIO)
P8_11 for MMC2_DAT1 (WL SDIO)
P8_16 for MMC2_DAT2 (WL SDIO)
P8_15 for MMC2_DAT3 (WL SDIO)
P8_18 for MMC2_CLK (WL SDIO)
P8_14 for GPIO WL_EN
P9_12 for GPIO BT_EN
P8_17 for GPIO WL_IRQ

These pin selections match a wifi/bluetooth cape and enabled them to quickly get to market without needing to debug new connectivity settings.

2 Likes

@ jkridner -

Thank you for taking the time to respond
Excellent response!