New Bela cape v.C3 - Can't use the analog outs

quintosardo

New capes, I noticed they are the new rev. C3.
I mounted one of these on a brand new Beaglebone Black.

Tried to run a simple test to use the analog ins and outs as usual, couldn't use them (always the same fixed, very low output).

I'm booting from the card.

I found a thread here about issues with the analog inputs, followed the solution from there:
- flashed the card with the latest version.
- updated bela software to the latest dev branch.

The analog inputs work, now (even though I didn't run accurate tests, but they respond).

The analog outputs don't react. While running the example, I can see the flashing blue led on the cape (close to the speaker outs) but the output stays fixed and close to zero.

I couldn't find documentation about this new rev.c. I also noticed some new sets of pads on it (GND-1-3, GND-5-7, etc.) but don't have info about them.

Anything simple I could be missing?

I tried three different units.

giuliomoro

quintosardo I also noticed some new sets of pads on it (GND-1-3, GND-5-7, etc.) but don't have info about them.

You should be able the analog out signals there, centered around ground (instead of in the 0V : 5V out range).

Also note that pins P8.32, P8.33, P8.34 and P8.38 are now in use by Bela cape Rev C and should not be used or connected for other purposes.

giuliomoro

Try running board_detect all in the console at the bottom of the IDE: what do you get?

Also, show the result of the "Version details" panel which you can access from the IDE -> settings ->Other system functions -> Version Details.

quintosardo

Ok, I'll try as soon as back to office!

quintosardo

giuliomoro About this (while going back to office to solve the no_out issue):
This is quite a bad surprise, now, as we were using those pins in a couple applications.
Are these new pins used for something that can be disabled? Are they for the analog ins and/or outs management?

quintosardo

Ok, result of board_detect all:

File /sys/devices/platform/ocp/ocp: P8_33_pinmux/state could not be opened
.
BelaRevC
BelaRevC
BelaRevC
BelaRevC
NoHardware

NOTE! every time I start the analog out example I get this message (the example runs):
"Es9080 without cape file for P8_33 requires you to set the pinmux some other way"

giuliomoro

quintosardo "Es9080 without cape file for P8_33 requires you to set the pinmux some other way"

yup, that denotes you didn't have the v0.3.8g , it should be gone by now.

quintosardo No, I can see they are fro the LEDs, converters enable and aud_dout2 (?)
I'll have to hack the PCB we made.

P8.32 is used for enabling analog ADC and DAC, P8.33 is the data out to the DAC, so both of these are required to be left alone. P8.34 and P8.38 are used for the LED so you can use them for your own purposes if the LED doesn't bother you, or remove the LED from the PCB if it does, then run the program with --disable-led.

quintosardo

Version details:

Image:
v0.3.8f, 4 January 2022

Core code:
Last updated on '25 lug 2023 09:03:16 '
from file 'Bela-dev'
via 'update_board'
Update was successful
Git desc: '8ba7caad-dirty'

quintosardo

Ok, now I see that I should have v.0.3.8h. I guess I followed a wrong path yesterday, trying to get the latest...

quintosardo

Ok, solved.

I don't know how I could get the v0.3.8f instead of the v0.3.8h, two days ago.
Updated to h (no need to update the Bela code to the dev branch) and everything looks right.

This was useful, at the end, as it raised that pins_used_by_Bela subject!
Can they be set free in any way and still use the analog ins and outs?

***Edit
No, I can see they are for the LEDs, converters enable and aud_dout2 (?)
I'll have to hack the PCB we made.

quintosardo

Thanks, everything working!

These are the only four pins that are being used out of the official list on the website, right?

giuliomoro

Yes those are the only extra pins. I also updated the list on the website, thanks for pointing it out (previously I had only updated the pdf).

quintosardo

giuliomoro Thanks a lot!

quintosardo

Oh, to close the subject: analog input and analog output voltage ranges remain the same as old versions, right?
"analog inputs have a range of 0V to 4.096V"
"analog outputs have a range of 0V to 5V"

giuliomoro

yes

quintosardo

I'm having hard times trying to have all the pins to fit to the new (for me, now that I learnt about rev.C3) configuration.
I was trying to use the last six in P8 (41 42 43 44 45 46) when I discovered that they are used by Bela Multiplexer.

Can I set them free if I'm not using the multiplexer?

Simply following the synchronous-gpio example doesn't work (I imagine they are allocated to the pru).

giuliomoro

quintosardo Can I set them free if I'm not using the multiplexer?

yes

apply

diff --git a/src/arm/BB-BELA-00A1.dts b/src/arm/BB-BELA-00A1.dts
index 3ad9285..fdf17b8 100644
--- a/src/arm/BB-BELA-00A1.dts
+++ b/src/arm/BB-BELA-00A1.dts
@@ -90,12 +90,6 @@
                        bela_pru_pins: pinmux_bela_pru_pins {
                                pinctrl-single,pins = <
                                        /* Pinmux for PRU */
-                                       0x0b0 0x25 /* pr1_pru1_pru_r30_4,       P8_41 | MODE5 | INPUT_PULLDOWN */
-                                       0x0b4 0x25 /* pr1_pru1_pru_r30_5,       P8_42 | MODE5 | INPUT_PULLDOWN */
-                                       0x0ac 0x25 /* pr1_pru1_pru_r30_3,       P8_44 | MODE5 | INPUT_PULLDOWN */
-                                       0x0a0 0x25 /* pr1_pru1_pru_r30_0,       P8_45 | MODE5 | INPUT_PULLDOWN */
-                                       0x0a4 0x25 /* pr1_pru1_pru_r30_1,       P8_46 | MODE5 | INPUT_PULLDOWN */
-                                       0x0a8 0x25 /* pr1_pru1_pru_r30_2,       P8_43 | MODE5 | INPUT_PULLDOWN */
                                        // Note: the below are not part of bela_pru_pins, however we cannot have them in a separate group
                                        // if there is no driver associated with it
                                        /* Is needed for pin multiplexing Bela button correctly */

to /opt/bb.org-overlays/src/arm/BB-BELA-00A1.dts
then do

rm -rf /opt/bb.org-overlays/src/arm/BB-BELA-00A1.dtbo && make -C /opt/bb.org-overlays/ all install

and reboot

quintosardo

Fantastic, thanks!