More importantly, I couldnt get neither SPI0 nor SPI1 working right off the bat. It took me a while to realize that SPI1 is also not enabled y default. I followed one of the previous comments and added the line ‘uboot_overlay_addr0=/lib/firmware/BB-SPIDEV1-00A0.dtbo’ to the /boot/uEnv.txt file. Upon rebooting I could see the data on the spidev. Now my question is whether what I have done is right or elegant. Did I miss any information that SPI1 is also not enabled by default? How could I have known (looking at a log file etc) that SPI wasnt enabled on startup?

PS:Thank you for this great forum. I am having a blast following your book and working on the bbb.

Thanks a lot conib. I was following the second edition too and was wondering why my RTC wasn’t recognized on i2c1. Your comment helped me figure it out.

I’m now working with the 2nd edition, and have installed the Debian 9.5 2018-10-7 LXQt release on my BeagleBone Black Rev. C.

From what I’m seeing, it looks like there may have been a couple of changes that have affected usage of the I2C buses.

1. When I do a

ls -l /sys/bus/i2c/devices/i2c-*

command, I see that the I2C1 bus (memory 0x4802A000) is now mapped to /dev/i2c-1, and the I2C2 bus (memory 0x4819C000) is now mapped to /dev/i2c-2.

Are you seeing that too?

As a result, to access my DS3231 RTC when it’s on pins P9_19 and P9_20, I needed to change the i2c bus specification in the i2cdetect, i2cdump, i2cget commands from a “1” to a “2”. Etc., etc.

I then decided to move my RTC to pins P9_17 and P9_18 and enable I2C1 (and so I was able to set up the RTC as specified on pp.350-352 in the 2nd edition).

But of course I2C1 was still disabled by default.

2. In order to enable the I2C1 bus, it turns out that what we need to do now* is set:

uboot_overlay_addr0=/lib/firmware/BB-I2C1-00A0.dtbo

in /boot/uEnv.txt

and then reboot.

*see Robert Nelson’s response https://groups.google.com/forum/#!category-topic/beaglebone/beagleboardorg-beaglebone-black/8vmFsH7K9JU

Hi Dhruv, yes, you are correct. Thanks for letting me know! Kind regards, Derek.

In Chapter8 Introduction to various buses, In I2C introduction you mentioned on Page No 277 7‐bit addressing is used, i.e., 0x00 to 0x80 (2^7 = 128(Decimal) = 0x80). I think 7 bit address do not include 0x80, 7 bits addresses from 0x00 to 0x7F ( total 128 not including 0x80). Sorry and please correct me if I am wrong.

Starting EBB SPI ADC Example
Response bytes are 0,0
This is the value 0 out of 1024.
End of EBB SPI ADC Example

Hey Phil
I believe you haven’t exported $SLOTS
What do you get when you type “echo $SLOTS”?
If it is empty set the value by typing (from page 233) “export SLOTS=/sys/devices/bone_capemgr.9/slots”

Ben

Hey Phil
I believe you havn’t exported $SLOTS
What do you get when you tpye “echo $SLOTS”?
If it is empty set the value by typing (from page 233) “export SLOTS=/sys/devices/bone_capemgr.9/slots”

Ben

Hi Dereck,
Thanks for your reply and valuable time.
I did some investigation using stty and it seems that my BBB ttyO4 got the canonical mode by default. So I added this line in the BBBEcho.c: options.c_lflag &= ~(ICANON|ECHO);

it is working fine with this but I don’t understand if I get this configuration because I updated the BBB SW recently

Thanks again

Kal

Trying to get UART4 going on 3.8.13 flavor.
When I type the correct command (as I understand it) I get the following:

root@e14BB-1:/lib/firmware# sudo sh -c “echo BB-UART4 > $SLOTS”
sh: 1: Syntax error: end of file unexpected

So not sure where to proceed next.

Thanks for your fine work.
Phil