May 19, 2022, 12:27:37 pm

Recent posts

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1
A20 / Re: Booting splash screen
Last post by JohnS - Today at 10:29:50 am
You may need SKIP instead of SEEK

John
2
A20 / Re: Custom image that defaults...
Last post by JohnS - Today at 10:28:12 am
Just a nudge: you may need SKIP instead of SEEK.

(Either way, I'd read what's there before replacing it.)

John
3
A20 / Re: [A20 Lime2] PWM on vanilla...
Last post by faraz - Today at 10:10:49 am
When PWM controller is enabled via Olinuxino-Overlays.
Only 1 PWM which is PWM0 at pin PB2 is enabled.
Below is how I enabled both PWMs. PWM0 at PB2 and PWM1 at PI3. Hope this can help someone.

First I installed device tree compiler using
sudo apt-get install device-tree-compilerThen I modified the code at https://github.com/OLIMEX/olinuxino-overlays/blob/master/sun7i-a20/sun7i-a20-pwm.dts to look like below

/dts-v1/;
/plugin/;

/ {
compatible = "allwinner,sun7i-a20";
description = "Enable PWM controller";

fragment@0 {
target = <&pio>;
__overlay__ {
pwm0_pin: pwm0-pin {
pins = "PB2";
function = "pwm";
};
};
};

        fragment@1 {
                target = <&pio>;
                __overlay__ {
                        pwm1_pin: pwm1-pin {
                                pins = "PI3";
                                function = "pwm";
                        };
                };
        };

fragment@2 {
target = <&pwm>;
__overlay__ {
pinctrl-names = "default";
pinctrl-0 = <&pwm0_pin>, <&pwm1_pin>;
status = "okay";
};
};
};

Then I compiled the .dts file into a .dtb file.
Code to compile
dtc -I dts -O dtb -o /home/sun7i-a20-pwm.dtbo /*path to the DTS file*/sun7i-a20-pwm.dts
Above code should compile the .dts file to a .dtbo file and place it in home.

Then I moved the .dtbo to /usr/lib/olinuxino-overlays/sun7i-a20/
It should replace the existing sun7i-a20-pwm.dtbo file
Then I rebooted the board and was able to generate PWM on both pins using below
From bash:
# cd /sys/class/pwm/pwmchip0/
# ls
device    export    npwm      power      subsystem  uevent    unexport
# echo 0 > export
The above enables pwm0, which should be at pin PB2
# cd pwm0
#ls
duty_cycle  enable      period      polarity    power      uevent
# echo 10000 > period
# echo 1000 > duty_cycle
# echo 1 > enable
# echo 0 > enable
# cd ../
# echo 1 > export
The above enables pwm1, which should be at pin PI3
# cd pwm1
#ls
duty_cycle  enable      period      polarity    power      uevent
# echo 10000 > period
# echo 1000 > duty_cycle
# echo 1 > enable
# echo 0 > enable

There might be typos in the code, so please double check.
4
A20 / Re: Custom image that defaults...
Last post by kimfaint - Today at 08:30:55 am
The end of the olimage guide only has instructions for rebuilding DTS and kernel.

However I found some instructions for rebuilding u-boot here: https://www.olimex.com/wiki/ArmbianHowTo#Building_u-boot

I have changed the board/olimex/a20_olinuxino/board.c file:
$ git diff
diff --git a/board/olimex/a20_olinuxino/board.c b/board/olimex/a20_olinuxino/board.c
index 19cc35ff27..f33f8fa27b 100644
--- a/board/olimex/a20_olinuxino/board.c
+++ b/board/olimex/a20_olinuxino/board.c
@@ -61,11 +61,11 @@ void spl_board_init(void)
        printf("\t\'olinuxino config list\' - Select your board\n");
        printf("\t\'olinuxino config write\' - Store the board configuration\n");
        printf("\t\'reset\' - Reset the board and load the configuration\n");
-      printf("\nUsing \'A20-OLinuXino-LIME\' as fallback configuration.\n\n");
+      printf("\nUsing \'A20-OLinuXino-LIME2\' as fallback configuration.\n\n");

        eeprom->header = OLINUXINO_EEPROM_MAGIC;
-      eeprom->id = 7739;
-      eeprom->revision.major = 'A';
+      eeprom->id = 8340;
+      eeprom->revision.major = 'E';
        eeprom->revision.minor = 0;
        eeprom->serial = 0;
        memset(eeprom->mac, 0xFF, 12);

and now successfully rebuilt the u-boot binary, which was essentially as easy as:
$ sudo apt install bison flex swig gcc-arm-linux-gnueabihf
$ make A20-OLinuXino_defconfig
$ make CROSS_COMPILE=arm-linux-gnueabihf-

Tomorrow I will try the Updating via USB part.

Though I am hoping I can just update the .img file with something like:
dd if=u-boot-sunxi-with-spl.bin of=A20-OLinuXino-bullseye-minimal-20220518-101434.img bs=1024 seek=8 conv=notrunc
5
New Product Ideas / Re: LibreSOC
Last post by SerjEpatoff - May 18, 2022, 11:29:09 pm
You're right but I can remember 2 guys which successfully designed their own MCUs and then fabricated them without zillions of $$$.

1. GA-144 144-core parallel FORTH chip by Charles Moore, creator of FORTH language.
2. Parallax Propeller and Propeller2 by Chip Gracey.

Both MCUs are very special and non-mainstream at all, they have their own niche and fanbase, that's why we can observe 2 rare cases of success.

Creating general-purpose SoC or MCU is lot harder: even if you design it perfectly, it will be too expensive per unit because of low production volumes.
6
New Product Ideas / Re: Tiny Linux board, maybe wi...
Last post by SerjEpatoff - May 18, 2022, 11:13:37 pm
Maybe Vocore2? Tiny OpenWRT board based on MT7628 router SoC.
https://vocore.io/

Pro:
MT7628 is ubiquitous (millions of cheap WiFi routers are based on it), Sigmastar SSD210 is like 'unobtanium': I can't find it in stock even on Alibaba and Baidu.

Con:
MT7628 is less powerful, 2x580MHz vs 2x1Ghz.
7
PIC / Re: ARM-USB-TINY-H as PIC prog...
Last post by KK1L - May 18, 2022, 06:52:07 pm
Thanks folks. I have a PIC-KIT3 coming. Was hoping to use what I already had available.  ICSP is definitely different than JTAG, but worth asking.
Thanks for your help and advice.

73 es God Bless de KK1L, Ron <><
8
A20 / Re: Custom image that defaults...
Last post by LubOlimex - May 18, 2022, 03:45:34 pm
I think it can be changed here:

https://github.com/OLIMEX/u-boot-olinuxino/blob/release-20220413/board/olimex/a20_olinuxino/board.c

around line 66:

eeprom->header = OLINUXINO_EEPROM_MAGIC;
eeprom->id = 7739;
eeprom->revision.major = 'A';
eeprom->revision.minor = 0;
eeprom->serial = 0;
memset(eeprom->mac, 0xFF, 12);

and then rebuild the u-boot and overwrite the u-boot of the card that you use.

Rebuilding u-boot is described at the end of the olimage guide.
9
A20 / Re: U-Boot Verifying data: Err...
Last post by kimfaint - May 18, 2022, 11:32:35 am
We have the same issue in not having reliable access to the EEPROM (https://www.olimex.com/forum/index.php?topic=8735.0) and need a method to force u-boot to default to a different board.  Being able to tweak some config in the /boot directory would be great.
10
A13 / Re: `openssl speed` causes res...
Last post by LubOlimex - May 18, 2022, 11:28:27 am
Looks like either insufficient power supply or overheating to me.

How do you power the board? Where exactly do you apply the power supply? What is the power rating of your power supply?
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