Here’s a quick Javascript bookmarklet I threw together for opening a new browser window showing an area in OpenStreetMap that is defined from extracting the current window’s URL and searching after useable values for latitude, longitude and zoom.
It grew out of an annoyance over Mapillary’s rendering of the Danish endpoint of the under construction HVDC Cobra Cable(more about it from 4C, even more from EnergiNet and the EU) in Endrup nearby where I live.
In Mapillary’s tiles rendering it is just a bunch of roads and a single POI indication. Whereas the Mapnik rendering shows the existing power infrastructure and the area under construction.
Well, I have been subjecting my oldstyle C brain to some Javascript lately so I decided to use that haemorrhage for attempting to put together a bookmarklet extracting coordinates from the current window’s URL and opening a new with the same approximate location in OSM.
It ended up like the below code block, and should also be usable on any other sites which receives locations via URL (both using HTTP GET notation with ‘?’ and locally in the page using anchors with ‘#’) and identifying them with key-value pairs using common names ({z,zoom},{lat},{lng,lon}). Note that this doesn’t include OpenStreetMap itself neither Google Maps as they only use the lat/lon values.
javascript:(function (){params={};kvs=document.location.href.split('&');kvs.forEach(function(kv){if(kv.indexOf('?'))kv=kv.substr(kv.indexOf('?')+1);if(kv.indexOf('#'))kv=kv.substr(kv.indexOf('#')+1);skv=kv.split('=');params[skv[0]]=skv[1];});window.open('http://openstreetmap.org/#map='+(params.z?params.z:13)+'/'+(params.lat?params.lat:55.5)+'/'+(params.lng?params.lng:(params.lon?params.lon:8.5)));console.log(params);})();
Copy and paste the above into the “Location” or “URL” of a bookmark and you’ll be able to click it to open a new OSM window on, at least for Mapillary maps pages, the same location as the original site. If nothing is found it will default to coordinates of my hometown of Esbjerg at 55.5/.8.5.
Here’s a prettified edition of the code:
params={}; kvs=document.location.href.split('&'); kvs.forEach(function(kv){ if(kv.indexOf('?')) kv=kv.substr(kv.indexOf('?')+1); if(kv.indexOf('#')) kv=kv.substr(kv.indexOf('#')+1); skv=kv.split('='); params[skv[0]]=skv[1]; }); window.open( 'http://openstreetmap.org/#map=' +(params.z?params.z:(params.zoom?params.zoom:13))+'/' +(params.lat?params.lat:55.5)+'/' +(params.lng?params.lng:(params.lon?params.lon:8.5)) ); console.log(params);
Stumbled across a very cheap RGB LED strip where I live in Denmark from the brand Frostlight. Priced at down to DKK 50 ~ EUR 6.5 ~ USD 7.5 in Fleggaard at Danish/German border but goes for around DKK 200 ~ EUR 26 ~ USD 30 in the ordinary DIY and internet shops (still cheap compared to other sources). For this amount you get a product which on the packaging is called “3 meter farvede LED bånd (RGB)” (which is a little gibberish Danish and not grammatically correct), English: “3 meter colored LED strip (RGB)”, containing these components;
According to the description this setup “does it all”; RGB multi color LEDS, controller doing colour change, fading etc.
The big question for me as a maker/hacker/tinkerer was; Does it use individually addressable LEDs?
And no, it doesn’t;
Obviously (as could be expected from the price), this strip is made from plain RGB LEDs with discrete R, G & B LEDS in a common anode setup (12V pin is common, current needs to be sinked from each RGB to control colour and intensity).
The brand Frostlight is unknown to me (they have a very non-informative website without any real product information), but they seem to supply LED products to many discount supermarkets in Denmark. They have a youtube channel (which is not even mentioned on the homepage) containing some product information. Even one for the “Frostlight LED farve-bånd”.
I was looking for a quick and cheap way to source LEDs for the awesome WordClock project by grahamvinyl (Arduino source code at github.com/grahamvinyl/WordClock_color_edit). However, it won’t work as all LEDs on the strip will light up in the same colour, but I consider using it for a cheaper tweak of it.
At least I’m confident I’ll find something to use the strip for anyway.
Edit 2023-04-23: on present day Ring is known instead as GNU Jami. Contact me using ring:f20607f4f974714ba91c664b153496fb931020e5 on the Ring distributed communication platform: ring.cx
Fra en tråd i Facebook-gruppen “Linux for begyndere“.
Spørgsmål Hvordan bliver man root bruger i linux mint ?? i grafisk brugerflade ??
Svar For fremtidig reference: Hvis man ønsker at køre en X-klient (et vilkårligt grafisk/GUI program) som root-brugeren, men vise dets vinduer på en X-server (typisk dit desktop environment/DE, som f.eks Gnome/KDE/Unity/lxde/xfce m.f.) der eksekveres af en ikke-privilegeret bruger kan man gøre som følger:
1) som X-server-brugeren kør kommandoen ‘xhost +’ i en grafisk konsol/terminal. Dette tillader at alle brugere og maskiner må vise vinduer på X-serveren (ja, X er en netværksprotokol). Tilladelsen bevares indtil X-serveren genstartes, eller den trækkes tilbage med ‘xhost -‘.
2) som root (su/sudo) eksekver det ønskede GUI-program, med specifikation af hvilken X-server og hvilket display dets vinduer ønskes vist på i DISPLAY environment-variablen (ja, det er muligt at køre flere separate X-servere/displays på samme maskine). Simpleste form med visning på display 0 på den lokale maskine vil være (med xterm-konsollen som eksempel) ‘DISPLAY=:0 xterm’. Vil man vise vinduet på en anden maskines X-server skal IP-adressen blot angives før ‘:’, som f.eks.: ‘DISPLAY=192.168.1.10:0 xterm’ (det er stadig en xterm der afvikles på den lokale maskine, vinduet vises blot på en ekstern X-server (ja, det kan være farligt, pas på).
Bemærk at man med sudo skal passe på at sætte env-vars i den rigtige shell. F.eks. vil sudo direkte foran ovenstående ikke virke da sudo afskærmer env af sikkerhedsgrunde. I stedet vil man kunne benytte følgende trick: sudo bash -c ‘DISPLAY=:0 xterm’ (enkelt citationstegn til -c er vigtigt).
Having used the Arduino prototyping platform (a loose combination of specific pieces of somewhat open/free hardware and a more open/free software stack) for some time for educational and tinkering purposes in my local hackerspace (geeklabs.dk) I have seen and studied the Arduino UNO hardware and lots of its “clones/compatibles/knockoffs” and their common MCU (MicroController Unit);
Atmel ATmega328P
I had begun wondering what the P in the microcontroller model name actually meant. So here is an attempt to decode the Atmel megaAVR chip numbering system. The other existing AVR based series UC3, tinyAVR, XMEGA, Battery & Automotive, will probably employ similar naming schemes.
The remainder of the product name following “ATmega” expresses the available flash memory and the approximate pin count of the package in an integer and optionally other features as either integer or letter (like the initial wondering of P in 328P above).
Starting with the integer, it is a concatenation of two separate integers encoding the flash size and pin count as defined below. The division of the two is non-ambiguous leaving some interpretation to be done.
1st integer: onboard flash size 8 = 4 KiB 8 = 8 KiB 16 = 16 KiB 32 = 32 KiB 64 = 64 KiB 128 = 128 KiB 256 = 256 KiB
2nd integer: total pin number (none) = standard pin count (differs) 8=28/32-pin 4= 40/44/49-pin 5= 64-pin 0= 100-pin
Suffix (char or integer), multiple possible P = picoPower (max. consumption 9mA@8MHz,5v vs. 12mA@8Mhz,5v for non-P) 9=LCD controller U2 = USB controller U4 = USB controller A = ?
Exceptions Note that some of the product names are completely void of these rules. Others employ different numbering but still with a familiarity to the above.
An example: ATmega6490A: 64KB flash, 100-pin, LCD Controller
Sources
Nedenfor et spørgsmål jeg kastede mig ud i at svare på i “Linux for Begyndere“-gruppen på Facebook, se den originale tråd.
For fremtiden vil jeg forsøge at samle et sammenkog af den hjælp og vejledning jeg yder på dansk i diverse roller i Spørgsmål & Svar-kategorien her på bloggen. Forhåbentlig vil andre kunne bruge det til noget, og i det mindste vil jeg selv kunne bruge det som reference ;).
Edit 2020-02-20: Som min erfaring heldigvis bød mig at handle efter skal man ikke stole på at universet er statisk, så status i dag er at ovennævnte gruppe og tråden med diskussionen, inklusiv mit svar, er fordampet fra Facebook, og jeg kan ikke finde nogle indikationer på hvad der er sket med den ellers ret aktive gruppe.
Uden at jeg kender UDOO nærmere, så er der uanset distribution og arkitektur to trin i processen at udvide en ext{2,3,4}- partition.
Until your device is sufficiently patched against the Stagefright vulnerabilty I recommend disabling automatic MMS retrieval on any Android phones from 2.2 and up (which is hopefully all in current use) to prevent unattended triggering.
Howtos for Google and Samsung devices are here.
Below are screenshots of how to do it on HTC One M7 using the stock (HTC Sense) messaging application called “SMS”. The procedure is likely to be very similar on most HTC devices using Sense. The UI shown is in Danish locale, the English menus will be something like SMS->Settings->Multi Media Messages (MMS)->Automatic Retrieval.
Schneier discusses details here and this seems to be the commit in CyanogenMod for the underlying problem in the media library. Check aælso the issue’s review page
Patch for u-boot mainline master (http://git.denx.de/u-boot.git) to prevent BBB’s to get stuck in a u-boot prompt because of spurious characters being received on the serial console (see http://www.mikini.dk/index.php/category/beaglebone-black/boot-issue).
diff –git a/include/configs/ti_am335x_common.h b/include/configs/ti_am335x_common.h index 5ed86d9..c58f467 100644 — a/include/configs/ti_am335x_common.h +++ b/include/configs/ti_am335x_common.h @@ -12,6 +12,12 @@ #ifndef __CONFIG_TI_AM335X_COMMON_H__ #define __CONFIG_TI_AM335X_COMMON_H__ +#define CONFIG_AUTOBOOT_KEYED +#define CONFIG_AUTOBOOT_STOP_STR “stop” +#define CONFIG_AUTOBOOT_PROMPT “autoboot in %d seconds (type ‘%s’ to abort)\n”,bootdelay,CONFIG_AUTOBOOT_STOP_STR +#define CONFIG_BOOT_RETRY_TIME 30 +#define CONFIG_RESET_TO_RETRY + #define CONFIG_AM33XX #define CONFIG_ARCH_CPU_INIT #define CONFIG_SYS_CACHELINE_SIZE 64 @@ -102,4 +108,7 @@ /* Now bring in the rest of the common code. */ #include <configs/ti_armv7_common.h> +#undef CONFIG_BOOTDELAY +#define CONFIG_BOOTDELAY 5 + #endif /* __CONFIG_TI_AM335X_COMMON_H__ */
diff –git a/include/configs/ti_am335x_common.h b/include/configs/ti_am335x_common.h index 5ed86d9..c58f467 100644 — a/include/configs/ti_am335x_common.h +++ b/include/configs/ti_am335x_common.h @@ -12,6 +12,12 @@ #ifndef __CONFIG_TI_AM335X_COMMON_H__ #define __CONFIG_TI_AM335X_COMMON_H__
+#define CONFIG_AUTOBOOT_KEYED +#define CONFIG_AUTOBOOT_STOP_STR “stop” +#define CONFIG_AUTOBOOT_PROMPT “autoboot in %d seconds (type ‘%s’ to abort)\n”,bootdelay,CONFIG_AUTOBOOT_STOP_STR +#define CONFIG_BOOT_RETRY_TIME 30 +#define CONFIG_RESET_TO_RETRY + #define CONFIG_AM33XX #define CONFIG_ARCH_CPU_INIT #define CONFIG_SYS_CACHELINE_SIZE 64 @@ -102,4 +108,7 @@ /* Now bring in the rest of the common code. */ #include <configs/ti_armv7_common.h>
+#undef CONFIG_BOOTDELAY +#define CONFIG_BOOTDELAY 5 + #endif /* __CONFIG_TI_AM335X_COMMON_H__ */
Patch and compiled binaries at http://www.mikini.dk/wp-content/uploads/2015/01/u-boot_mainline_BBB-autoboot-patch_201501151.zip.
Install the new u-boot by copying the files “MLO” and “u-boot.img” to the root directory of your boot device (first FAT-partition on your SD-card or onboard MMC). Using the stock Debian image (http://beagleboard.org/latest-images) this can be done via USB by powering the board from your computers USB-interface, waiting for the BBB to boot and register its drive as an usb mass-storage in your OS. Now use your favorite file management application to copy the files from the above zip-file replacing the existing files.
Disclaimer: this is mostly an experiment, there is a lot of u-boot trees and patches floating around for the BBB (like https://github.com/beagleboard/u-boot), so probably mainline hasn’t got the most recent stuff for AM335x/BBB yet.
This is test report 3 in the series of tests on the “BBB doesn’t boot” issue, discussed here on the BBB mailing list.
The present test is accompanying this specific post in the discussion thread.
The goal of the test is to establish under which conditions the U15.2 (1A) input provides a stable boot experience. The four test subjects are a strong pull down of 990 ohm and 0 ohm, and voltage divider circuits using 0 ohm and 1k ohm fixing the voltage at respectively 3.3V and 0.58V.
The strong pull down of 990 ohm and 0 ohm on B_UART0_RX doesn’t prove successful, as was also the case with the weaker pull down of 45k2 ohm in test report 2, and the factory mounted pull down of 100k ohm.
But providing a stable 3.3V or 0.58V using a voltage divider with resistor values 0 ohm and 1k ohm results in a booting BBB in every test case!
This is analogous with the result of test 2 in test report 2, which established the same fact, but for B_UART0_RX = 1.81V using a 82k5 ohm resistor.
The second picture below shows an easy and safe way to establish the condition of test 3 as a permanent fix on the backside of the BBB pcb. It places an insulated wire between VDD_3V3B from terminal 5 on the non-populated P2″CTI JTAG, DNI” header and the B_UART0_RX signal on J1 (UART0 Serial Port) pin 4.
(formatted in nice emacs org-mode)
* BBB boot lockup test report 3 ** Equipment *** Device Under Test Beaglebone Black (BBB) produced by Element 14 (PCB REV B6, serial EM-400524+XA6001961, marked "Element 14"). *** Device Under Test #1 Modify DUT by applying an additional 1k ohm pull down resistor in parallel to R165 from J1.4 (B_UART0_RX)/U15.2 (1A) to P8.1 (DGND), thus forming a very strong pull down on B_UART0_RX with resistive value of 1/(1/1k+1/82k5)= 990.1 ohm. *** Device Under Test #2 Modify DUT by applying a short circuit from from J1.4 (B_UART0_RX)/U15.2 (1A) to P8.1 (DGND), thus forcing 0V on B_UART0_RX. *** Device Under Test #3 Modify DUT by applying a short circuit from J1.4 (B_UART0_RX)/U15.2 (1A) to P8.4 (VDD_3V3B), thus forcing 3.3V on B_UART0_RX. *** Device Under Test #4 Modify DUT by applying a 470k ohm pull up resistor from J1, pin 4 (B_UART0_RX, U15-pin 2, signal 1A) to P8, pin 4 (VDD_3V3B), effectively creating a voltage divider with existing pull down resistor R165 (100k ohm) fixing voltage on B_UART0_RX to 3.3V*100k/(470k+100k)= 0.58V. *** Power Supply Unit Huawei HW-050200E3W, output 5V 2A, USB A-connector. Danish plug. Sourced from Huawei E589 mobile wifi. *** Power Cable 20 cm no-name USB A male connector to USB Mini-B male connector. ** Test 1+2+3+4 Procedure For test 1 use DUT#1, for test 2 use DUT#2, for test 3 use DUT#3, for test 4 use DUT#4. Connect cable Mini-B male to DUT USB Mini-B female. Insert PSU into mains socket. Test boot capability of DUT by inserting the cable's USB A connector into the PSU while keeping the USB Mini-B connector inserted into the DUT. Then verify that the power led (D1) light up, and note whether boot succeeded or failed by watching if USR0-USR3 leds (D2-D5) lights up indicating boot. Then remove the A connector from the mains adaptor inserting it immediately repeating the test. Results can be seen in section Test Results. ** Interpretation Test 1 failure rate= 2 fails/60 boots= *3.33%* Test 2 failure rate= 3 fails/60 boots= *5.00%* Test 3 failure rate= 0 fails/100 boots= *0.00%* Test 4 failure rate= 0 fails/60 boots= *0.00%* The tests 1 & 2 shows that forming first a strong pull down (replacing 100k with 9k1) and then a short forcing 0V on B_UART0_RX, doesn't prevent the failure to occur. Whereas test 3+4 shows that forming a voltage divider which fixes the voltage instead of just pulling up/down indeed makes the system boot at every power up. Overall this indicates that the flickering of U15's output 1Y could be caused internally in U15 by a spurious input signal on input 1A during power up. This can't be elleviated by inserting pull-up/downs, but creating a stable input signal on 1A by a voltage divider does solvs the boot issue, disregarding whether this voltage is low (0.58V) or high (3.3V). ** Test results | Boot no. | Test 1 | Test 2 | Test 3 | Test 4 | | 1 | boot | no boot | boot | boot | | 2 | boot | boot | boot | boot | | 3 | boot | boot | boot | boot | | 4 | boot | boot | boot | boot | | 5 | boot | boot | boot | boot | | 6 | boot | boot | boot | boot | | 7 | boot | boot | boot | boot | | 8 | boot | boot | boot | boot | | 9 | boot | boot | boot | boot | | 10 | boot | boot | boot | boot | | 11 | boot | boot | boot | boot | | 12 | boot | boot | boot | boot | | 13 | boot | boot | boot | boot | | 14 | boot | boot | boot | boot | | 15 | boot | boot | boot | boot | | 16 | boot | boot | boot | boot | | 17 | boot | no boot | boot | boot | | 18 | boot | boot | boot | boot | | 19 | boot | boot | boot | boot | | 20 | boot | boot | boot | boot | | 21 | boot | boot | boot | boot | | 22 | boot | boot | boot | boot | | 23 | boot | boot | boot | boot | | 24 | boot | boot | boot | boot | | 25 | boot | boot | boot | boot | | 26 | boot | boot | boot | boot | | 27 | no boot | boot | boot | boot | | 28 | boot | no boot | boot | boot | | 29 | boot | boot | boot | boot | | 30 | boot | boot | boot | boot | | 31 | boot | boot | boot | boot | | 32 | boot | boot | boot | boot | | 33 | boot | boot | boot | boot | | 34 | boot | boot | boot | boot | | 35 | boot | boot | boot | boot | | 36 | boot | boot | boot | boot | | 37 | boot | boot | boot | boot | | 38 | no boot | boot | boot | boot | | 39 | boot | boot | boot | boot | | 40 | boot | boot | boot | boot | | 41 | boot | boot | boot | boot | | 52 | boot | boot | boot | boot | | 53 | boot | boot | boot | boot | | 44 | boot | boot | boot | boot | | 45 | boot | boot | boot | boot | | 46 | boot | boot | boot | boot | | 47 | boot | boot | boot | boot | | 48 | boot | boot | boot | boot | | 49 | boot | boot | boot | boot | | 50 | boot | boot | boot | boot | | 51 | boot | boot | boot | boot | | 52 | boot | boot | boot | boot | | 53 | boot | boot | boot | boot | | 54 | boot | boot | boot | boot | | 55 | boot | boot | boot | boot | | 56 | boot | boot | boot | boot | | 57 | boot | boot | boot | boot | | 58 | boot | boot | boot | boot | | 59 | boot | boot | boot | boot | | 60 | boot | boot | boot | boot | | 61 | ------- | -------- | boot | ------- | | 62 | | | boot | | | 63 | | | boot | | | 64 | | | boot | | | 65 | | | boot | | | 67 | | | boot | | | 68 | | | boot | | | 69 | | | boot | | | 70 | | | boot | | | 71 | | | boot | | | 72 | | | boot | | | 73 | | | boot | | | 74 | | | boot | | | 75 | | | boot | | | 76 | | | boot | | | 77 | | | boot | | | 78 | | | boot | | | 79 | | | boot | | | 80 | | | boot | | | 81 | | | boot | | | 82 | | | boot | | | 83 | | | boot | | | 84 | | | boot | | | 85 | | | boot | | | 86 | | | boot | | | 87 | | | boot | | | 88 | | | boot | | | 89 | | | boot | | | 90 | | | boot | | | 91 | | | boot | | | 92 | | | boot | | | 93 | | | boot | | | 94 | | | boot | | | 95 | | | boot | | | 96 | | | boot | | | 97 | | | boot | | | 98 | | | boot | | | 99 | | | boot | | | 100 | | | boot | | | | | | ------ | |
Investigating further on the BBB boot issue described in this earlier post and following discussion in the mailinglist, here is a test of another BBB modification trying to remedy this.
This time the modification is done on the non-cpu side of U15 (75LVC2G241 buffer/driver), where the buffered uart0 input (B_UART0_RX) is kept stable using a voltage divider. B_UART0_RX is already pulled low by a 100k resistor, but adding another 82k5 ohms pulling against 3,3v makes up a voltage divider, keeping input 1A on U15 stable at all times at approx. half (~55%) of the voltage between VDD_3V3B and DGND. At stable 3,3V that voltage will be 3.3V*100k/(82k5+100k)= 1.81V (EDIT: first edition of this post erroneously stated the voltage drop of ~1.4V over the pull up as the B_UART0_RX’s voltage level).
Beware that this modification might affect the functionality of uart0 rx capability. I’ll probably test this some time soon (TM) when I got access to my TTL<->USB converter.
These results are summed up in this post on the BBB mailinglist.
Providing a stable B_UART0_RX at 1.8V results in a booting BBB in every test case!
The third picture below shows an easy and relatively safe way to make this a permanent fix on the backside of the BBB. It places a resistor (this one is 82k5 ohm ) between VDD_3V3B from terminal 5 on the non-populated P2 header marked as “CTI JTAG, DNI” and the B_UART0_RX signal on J2 (UART0 Serial Port) pin 4.
Mocked up voltage divider keeping B_UART0_RX stable. Test equipment and setup. First attempt at a more robust modification on the solder side of the PCB.
* BBB boot lockup test report 2 ** Equipment*** Device Under Test #1 Unmodified Beaglebone Black (BBB) produced by Element 14 (PCB REV B6, serial EM-400524+XA6001961, marked "Element 14"). *** Device Under test #2 Modify DUT#1 by applying a 82k5 ohm pull up resistor from J1, pin 4 (B_UART0_RX, U15-pin 2, signal 1A) to P8, pin 4 (VDD_3V3B), effectively creating a voltage divider with existing pull down resistor R165 (100k ohm) fixing voltage on B_UART0_RX to 3.3V*100k/(82k5+100k)= 1.81V. *** Device Under Test #3 Modify DUT#1 by applying a 82k5 ohm pull down resistor from J1, pin 4 (B_UART0_RX, U15-pin 2, signal 1A) to P8, pin 1 (DGND), thus forming a stronger pull down on B_UART0_RX with resistive value of 1/(1/100k+1/82k5)= 45k2 ohm *** Power Supply Unit Huawei HW-050200E3W, output 5V 2A, USB A-connector. Danish plug. Sourced from Huawei E589 mobile wifi. *** Power Cable 20 cm no-name USB A male connector to USB Mini-B male connector. ** Test 1 Procedure Insert PSU into mains socket. Test boot capability of DUT#1 by inserting the USB A connector into the mains socket adaptor while keeping the USB Mini-B connector inserted into the BBB. Then verify that the power led light up, and note whether boot succeeded or failed by watching if USR0-USR3 lights up indicating boot. Then remove the A connector from the mains adaptor wait 3 seconds and repeat. Results can be seen in section Test Results, column Test 1. ** Test 2 Procedure Repeat Test 1 procedure using DUT#2. Results can be seen in section Test Results, column Test 2. ** Test 3 procedure Repeat Test 1 procedure using DUT#3. Results can be seen in section Test results, column Test 3. ** Interpretation DUT#1 failure rate= 4 fails/65 boots= *6,2%* DUT#2 failure rate= 0 fails/50 boots= *0,0%* DUT#3 failure rate= 3 fails/50 boots= *6.0%* Test 2 in reference to Test 1 shows that fixing B_UART0_RX to 1.4v using a voltage divider increases the system boot success rate from 94% to 100%. Though the modification might affect the functionality of uart0 rx capability. Test 3 shows that forming a stronger pull down on B_UART0_RX (100k->45k), dosn't change the failure rate as might be expected. This suggest that some strong (internal?) signal that a pull down in itself can't correct is driving the the 75LVC2G241's 1A input sometime during powerup. ** Test results | Boot no. | Test 1 | Test 2 | Test 3 | | 1 | boot | boot | boot | | 2 | boot | boot | boot | | 3 | boot | boot | boot | | 4 | boot | boot | boot | | 5 | boot | boot | boot | | 6 | boot | boot | boot | | 7 | boot | boot | boot | | 8 | boot | boot | boot | | 9 | boot | boot | boot | | 10 | boot | boot | boot | | 11 | boot | boot | boot | | 12 | boot | boot | boot | | 13 | boot | boot | boot | | 14 | boot | boot | boot | | 15 | boot | boot | boot | | 16 | boot | boot | boot | | 17 | boot | boot | boot | | 18 | boot | boot | boot | | 19 | boot | boot | boot | | 20 | boot | boot | boot | | 21 | no boot | boot | boot | | 22 | boot | boot | boot | | 23 | boot | boot | boot | | 24 | boot | boot | boot | | 25 | boot | boot | boot | | 26 | boot | boot | boot | | 27 | boot | boot | boot | | 28 | boot | boot | boot | | 29 | boot | boot | boot | | 30 | boot | boot | boot | | 31 | boot | boot | boot | | 32 | boot | boot | boot | | 33 | boot | boot | no boot | | 34 | boot | boot | no boot | | 35 | boot | boot | boot | | 36 | boot | boot | boot | | 37 | boot | boot | boot | | 38 | no boot | boot | boot | | 39 | boot | boot | boot | | 40 | boot | boot | boot | | 41 | boot | boot | boot | | 52 | boot | boot | boot | | 53 | boot | boot | boot | | 44 | boot | boot | no boot | | 45 | no boot | boot | boot | | 46 | boot | boot | boot | | 47 | boot | boot | boot | | 48 | boot | boot | boot | | 49 | boot | boot | boot | | 50 | boot | boot | boot | | 51 | boot | | | | 52 | boot | | | | 53 | boot | | | | 54 | boot | | | | 55 | boot | | | | 56 | boot | | | | 57 | boot | | | | 58 | boot | | | | 59 | boot | | | | 60 | boot | | | | 61 | boot | | | | 62 | boot | | | | 63 | boot | | | | 64 | boot | | | | 65 | no boot | | |
* BBB boot lockup test report 2 ** Equipment*** Device Under Test #1 Unmodified Beaglebone Black (BBB) produced by Element 14 (PCB REV B6, serial EM-400524+XA6001961, marked "Element 14").
*** Device Under test #2 Modify DUT#1 by applying a 82k5 ohm pull up resistor from J1, pin 4 (B_UART0_RX, U15-pin 2, signal 1A) to P8, pin 4 (VDD_3V3B), effectively creating a voltage divider with existing pull down resistor R165 (100k ohm) fixing voltage on B_UART0_RX to 3.3V*100k/(82k5+100k)= 1.81V.
*** Device Under Test #3 Modify DUT#1 by applying a 82k5 ohm pull down resistor from J1, pin 4 (B_UART0_RX, U15-pin 2, signal 1A) to P8, pin 1 (DGND), thus forming a stronger pull down on B_UART0_RX with resistive value of 1/(1/100k+1/82k5)= 45k2 ohm
*** Power Supply Unit Huawei HW-050200E3W, output 5V 2A, USB A-connector. Danish plug. Sourced from Huawei E589 mobile wifi.
*** Power Cable 20 cm no-name USB A male connector to USB Mini-B male connector.
** Test 1 Procedure Insert PSU into mains socket. Test boot capability of DUT#1 by inserting the USB A connector into the mains socket adaptor while keeping the USB Mini-B connector inserted into the BBB. Then verify that the power led light up, and note whether boot succeeded or failed by watching if USR0-USR3 lights up indicating boot. Then remove the A connector from the mains adaptor wait 3 seconds and repeat.
Results can be seen in section Test Results, column Test 1.
** Test 2 Procedure
Repeat Test 1 procedure using DUT#2.
Results can be seen in section Test Results, column Test 2.
** Test 3 procedure
Repeat Test 1 procedure using DUT#3.
Results can be seen in section Test results, column Test 3.
** Interpretation
DUT#1 failure rate= 4 fails/65 boots= *6,2%* DUT#2 failure rate= 0 fails/50 boots= *0,0%* DUT#3 failure rate= 3 fails/50 boots= *6.0%*
Test 2 in reference to Test 1 shows that fixing B_UART0_RX to 1.4v using a voltage divider increases the system boot success rate from 94% to 100%. Though the modification might affect the functionality of uart0 rx capability.
Test 3 shows that forming a stronger pull down on B_UART0_RX (100k->45k), dosn't change the failure rate as might be expected. This suggest that some strong (internal?) signal that a pull down in itself can't correct is driving the the 75LVC2G241's 1A input sometime during powerup.
** Test results
| Boot no. | Test 1 | Test 2 | Test 3 | | 1 | boot | boot | boot | | 2 | boot | boot | boot | | 3 | boot | boot | boot | | 4 | boot | boot | boot | | 5 | boot | boot | boot | | 6 | boot | boot | boot | | 7 | boot | boot | boot | | 8 | boot | boot | boot | | 9 | boot | boot | boot | | 10 | boot | boot | boot | | 11 | boot | boot | boot | | 12 | boot | boot | boot | | 13 | boot | boot | boot | | 14 | boot | boot | boot | | 15 | boot | boot | boot | | 16 | boot | boot | boot | | 17 | boot | boot | boot | | 18 | boot | boot | boot | | 19 | boot | boot | boot | | 20 | boot | boot | boot | | 21 | no boot | boot | boot | | 22 | boot | boot | boot | | 23 | boot | boot | boot | | 24 | boot | boot | boot | | 25 | boot | boot | boot | | 26 | boot | boot | boot | | 27 | boot | boot | boot | | 28 | boot | boot | boot | | 29 | boot | boot | boot | | 30 | boot | boot | boot | | 31 | boot | boot | boot | | 32 | boot | boot | boot | | 33 | boot | boot | no boot | | 34 | boot | boot | no boot | | 35 | boot | boot | boot | | 36 | boot | boot | boot | | 37 | boot | boot | boot | | 38 | no boot | boot | boot | | 39 | boot | boot | boot | | 40 | boot | boot | boot | | 41 | boot | boot | boot | | 52 | boot | boot | boot | | 53 | boot | boot | boot | | 44 | boot | boot | no boot | | 45 | no boot | boot | boot | | 46 | boot | boot | boot | | 47 | boot | boot | boot | | 48 | boot | boot | boot | | 49 | boot | boot | boot | | 50 | boot | boot | boot | | 51 | boot | | | | 52 | boot | | | | 53 | boot | | | | 54 | boot | | | | 55 | boot | | | | 56 | boot | | | | 57 | boot | | | | 58 | boot | | | | 59 | boot | | | | 60 | boot | | | | 61 | boot | | | | 62 | boot | | | | 63 | boot | | | | 64 | boot | | | | 65 | no boot | | |
