problem loading SPI overlay

[mzimmers]

Hi -

I really hate to ask this question here, since I'm sure I'm doing something obviously wrong, but...I'm trying to duplicate Dr. Molloy's example in his book, and I'm getting an error:

mzimmers@beaglebone:/lib/firmware$ pwd

/lib/firmware

mzimmers@beaglebone:/lib/firmware$ cat $SLOTS

 0: PF----  -1 

 1: PF----  -1 

 2: PF----  -1 

 3: PF----  -1 

 4: P-O-L-   0 Override Board Name,00A0,Override Manuf,cape-universaln

mzimmers@beaglebone:/lib/firmware$ sudo sh -c "echo BB-SPIDEV0 > $SLOTS"

sh: echo: I/O error

mzimmers@beaglebone:/lib/firmware$ cat $SLOTS

 0: PF----  -1 

 1: PF----  -1 

 2: PF----  -1 

 3: PF----  -1 

 4: P-O-L-   0 Override Board Name,00A0,Override Manuf,cape-universaln

mzimmers@beaglebone:/lib/firmware$ 

I've tried it a few times...same results. What am I screwing up here?

Thanks...

[Robert Nelson]

On Tue, Jun 13, 2017 at 8:11 PM, mzimmers <mzim...@gmail.com> wrote:
> Hi -
>
> I really hate to ask this question here, since I'm sure I'm doing something
> obviously wrong, but...I'm trying to duplicate Dr. Molloy's example in his
> book, and I'm getting an error:
>
> mzimmers@beaglebone:/lib/firmware$ pwd
> /lib/firmware
> mzimmers@beaglebone:/lib/firmware$ cat $SLOTS
> 0: PF---- -1
> 1: PF---- -1
> 2: PF---- -1
> 3: PF---- -1
> 4: P-O-L- 0 Override Board Name,00A0,Override Manuf,cape-universaln

cape universal is already loaded, thus the pins are taken..

open /boot/uEnv.txt

remove the:

cape_universal=enabled

option

or just use "config-pin" to set the pins as spi

Regards,

--
Robert Nelson
https://rcn-ee.com/

[Robert Nelson]

On Wed, Jun 14, 2017 at 9:01 AM, Michael Zimmers <mzim...@gmail.com> wrote:
> Hi, Robert - thanks for the tip. The echo command no longer fails, but the $SLOTS file isn’t updated. Any other suggestions?
>

type:

dmesg | tail

and see what happend..

[Robert Nelson]

On Wed, Jun 14, 2017 at 9:08 AM, Michael Zimmers <mzim...@gmail.com> wrote:
> Oh, interesting…I misspoke: the overlay was successful, but instead of appending it to the list, it replaced entry #4. Not what I was expecting from Dr. Molloy’s example. Did this happen because I disabled that universal entry?

It didn't replace anything, the first 4 entries are tied to the cape
eeprom standard, anything after that is just a list of virtual capes..