I’ve been using the latest dev builds everyday for iPod Nano 2G and still encountering “Swapped Channels” on Playback (e.g. Left Channel → Right Headphone / Right Channel → Left Headphone).

Used latest build 5785cfb-120625

So far there's still two problem which have never been fixed on Android:
1.When opening Rockbox, its volume bump to max automatically whatever it was when last quit;
2.On most HTC(and probably other) devices one can't use physical volume keys to adjust. Volume bars in WPS and SBS work well however.

Hopes the fixes!

I noticed various RDS-related issues on my Clip Zip and Samsung R0

1) Sansa Clip Zip
With the latest builds (for example version 341e2c4-120929) I noticed the RDS text just behaves crazy, like blinking for no reason and displaying strange characters. Besides, the RDS name won't display most of time or at least needs much time to display.
When reverting back to an older build (0c4bd3a-120406 for example), the RDS name displays quickly and for all stations now and the RDS text is just displaying and scrolling normally.
Tested and noticed with my theme lebellium Samsung -like: http://themes.rockbox.org/index.php?themeid=1681 and with the various DFKT Minimum Zip themes (this one for example: http://themes.rockbox.org/index.php?themeid=1539 )
screenshots of the issue: http://imageshack.us/a/img855/8724/dump120926124155.png http://imageshack.us/a/img837/2154/dump120926124439.png

2) Samsung YP-R0
In addition to the RDS issues reported for the Zip above that also exist on the R0, it seems that the RDS text makes the device crash after a few seconds or minutes with my theme lebellium Samsung-like (version 1.60 beta to download in attachment).
I found 2 unsatisfying ways to bypass this annoying crash:
-Remove the %s scrolling tag for the RDS text, that is to say replace "%s%ac%tz" by "%ac%tz". But that's not a good solution since then the RDS text is cut off. The %tz tag only makes sense when associated with a %s tag and all other themes supporting RDS use it and work well that way.
-Replace the RDS text font (currently 20-DroidSans-Bold.fnt) by another font from the Rockbox Font Pack. As I want a nice anti-aliased font, the only acceptable alternative I found is the Ubuntu Bold font. But this font makes the device crash too…

So I just hope there is a bug somewhere that can be fixed?

Sans Clip V2

24bit 96000 Hz 6 Channel (5.1) FLAC files skip to next song after 30 seconds. 30 seconds is an estimate because my screen is broken, so I can’t see what’s happening. I downloaded a daily build 3 days ago, but I think it’s a buffering issue. Flac is 8181 kbps (says Foobar).

It’s the first time I tried these files, so I don’t know if they ever worked, or ever will.
If they never will work, I’m sorry for reporting this.

Thank you all for your time and efforts.

First approach, to add dma read/write disk access to the sansa.

There are some restrictions on the dma functionality with this patch:
- only stabile at 80MHz ⇒ cpu boost control added to the driver
- only on 16byte aligned data ptr ⇒ all data are copied to/from aligned memory
- no interrupt support ⇒ using polling method

At 30MHz the driver is much more stable with the following PLL settings:
PLL_CONTROL = 0x8a221e0c; /* 30 MHz = (48MHz/12*30) / 4 */
CLOCK_SOURCE = 0×40007777; /* source #1, #2, #3, #4: PLL (#4 active) */

Reading seems to be in general more reliable than writing of the cards.
The data throughput is a little worse than in the current implementation.
This is partly due to the data copying.
The sporadical ‘2bytes inserted’ problem with the USB file transfer is still
there. Interestingly @30MHz with the above settings, there is another problem:
sporadically ‘2bytes missing’ and ‘2bytes inserted’. Perhaps the DMA transfer
needs some more initialization for proper synchronization.

I’m using several SD-cards with my Sansa. When switching cards
and updating the database the db entries of other cards are lost
(unless saved to the database log).

In order to differentiate between files from different cards the
easiest way is to give them different path names. So instead of
mounting each card to <microSD1> this patch takes the volume label
i.e. ‘Classic1’ of the filesystem and mounts it to <Classic1>.

The database update is modified in a way that it erases only entries
for files with a filename of a mounted filesystem. So data of other
cards isn’t erased.

So far the database search isn’t modified to handle nonexisting files,
you still get albums etc. which are currently unavailable.
The patch only makes sure that nonexisting files aren’t entered into
the current playlist.

The patch is only activated for Sansa e200, as I couldn’t test it for
other players.

Note: This is work in progress.
Status: Code implemented

      Manual not updated
      Wiki not updated (only after commit)

The idea of this patch is to have the same keyboard keys assign to the same actions in all platforms.

For example, have +/- keys (both on keyboard and on Numpad) are assigned to Volume Up and Volume Down keys of the original platform.
For platforms which do not have these keys, pressing the +/- keys in the simulator will do nothing.

This change will help developers to do manual regression testing on lots of platforms easily, as they do not have to memorize each platform’s key assignment.

Future development: Display key assignment on screen, and/or on console

This patch modifies the Gigabeat S keymap so that it can be used almost solely using the buttons on the face of the player.

Currently, there is an unused button in the WPS screen (the BACK button, up-left from the cross) which in my mind makes more sense as the “back to the menu” button, while the MENU button (up-right from the cross) is the logical Play/Pause button (at least to a right-handed individual). It’s unfortunate that the button with the Windows logo has been called the MENU button in the code, thus making this rather confusing to read, but if enough people agree with the feel of this change, that could be modified as well.

I noticed that when filling the buffer my Video iPod (32MB RAM) does noticeable seeks at semi-regular intervals even if reading from a single non-fragmented file. It seems this is due to having to read the next FAT sector. In firmware/drivers/fat.c there is a FAT cache but no read-ahead of the FAT.

I created fat_preload( struct fat_file *file, long sectorcount ) in firmware/drivers/fat.c to preload the FAT cache. In firmware/common/file.c I created file_preloadfat(int fd, size_t count) because calling a fat_ function directly would be too much of a kludge. I use file_preloadfat in apps/buffering.c just before filling the buffer.

This got rid of that regular seeking and it seems to it can remove about two seconds from the time needed to fill the buffer when reading a single non-fragmented file. Currently the code is quite simple and unintelligent. Fragmentation or other activity can overwrite the pre-loaded FAT sectors in the cache, and in such cases the pre-load leads to needless extra reads. More work is probably needed before this can be included in Rockbox.

Currently this patch is for SW-codec only. I think file_preloadfat could be called from HW-codec buffering code also, though few seeks would be prevented with 2MB of RAM. This patch is also probably useless with flash storage.

i asked some time ago why there is the buttontable in general settings –>bookmark. i wondered because the buttons are the same as in other lists. Marc Guay said "the delete button is unique", an i wondered why there is a dedicated delete button… in no other lists exists such a button afaik.

i changed the manual accordingly.
i also corrected some wrong (?) comments.
i hope i did everything right, at least for the e200 it compiles and works fine.

i would like to get some opinions about it.

This patch enables you to control the simulator using a named pipe to provide simulated keypresses, rather than the keyboard.

Unfortunately there is a bug that means that not all events seem to have any effect. On the e200 sim, I can use the scroll buttons to move in the main menu, but neither RIGHT nor SELECT lets me enter any of the entries. I suspect it's related to repeat or hold/release handling, but I'm not sure how to fake that properly.

A new background image for bubbles that looks a lot better.
Made using GIMP and images from frozen bubble.

Copy the attached file to ‘apps/plugins/bitmaps’.

This patch adds a secondary backlight timeout (similar to what the the iPod OF does).

It adds two extra settings: secondary backlight timeout and secondary brightness (I'm not sure wrt the naming of those, any suggestions?)

The code isn't very clean, but it works (except for CONFIG_BACKLIGHT_FADING == BACKLIGHT_FADING_PWM targets, for which I haven't implemented this).

Please test this.

Steps to reproduce:

1. Create a directory: /AUDIO;BOOKS
2. Place a file in it: /AUDIO;BOOKS/file.mp3
3. Start playing the file, and then create a bookmark
4. Do “List bookmarks” for the file
5. The bookmark menu lists something like this:

BOOKS/;file
0:02, 2, Shuffle

The problem seems to be that .bmark files use semicolons to separate the fields of information. If there’s a semicolon in the path, it thinks that it indicates the end of the path and the beginning of the filename.

Here’s a patch to version r29143M-110324 that adds the Zipit Z2 as a build target. It requires one new file (also attached) firmware/target/hosted/zipit/powermgmt-zipit-z2.c to monitor the battery.

This is mostly a generic SDL app with a few tweaks for the Zipit buttons and battery monitoring. The patch also includes a few small bug fixes for SDL app builds. I had to fix the labels in the asm section of lcd-16bit.c. There were some missing parenthesis on an #ifdef in button-application.c. And the apps/SOURCES file needs an #ifdef to handle an SDL app build without touchscreen support.

The patch allows to use the persistent dircache even in targets that do not define HAVE_EEPROM_SETTINGS.

Starting trying to implement such a feature for my iPod Video, I "discovered" the functions dircache_load/save (I have a slight knowledge of the RB software). Investigating why it was not used on my target, I saw that it's conditioned to the define HAVE_EEPROM_SETTINGS without an apparently reason to limit them just to some targets.
So, I simply "detach" the functions definition and use from the define.
I'm using it since an hour, starting up and shutting down the DAP various times, jumping back and forth inside the dynamic play list, and I got no problems at all.

If I guess correctly the code, the dircache should be updated also when changing the DAP content, if the USB connection is done by RB and not the OF.

It's applied to r29907.

The location for recordings can be set, but the only way to see the current value for the setting is to look into the config file. The patch adds a note stating that to the manual.

Also, there is a known bug ( FS#12517 ,  FS#12500 ) preventing saving the recorded files in the root directory (maybe this applies only to some targets, not all). The patch adds a warning about that.

When the dc jack is plugged in to charge while the player is not running (switched off), the display says ‘ATA Error -11’. It can’t be reset except by removing the batteries and dc jack. I ran an older build from last year and it works fine.

Recipe:
1) Play an album. Wait until buffering completes.
2) Skip from track 1 to track 2. No buffering occurs.
3) Skip from track 2 to track 1. No buffering occurs.
4) In the playlist viewer, select track 2. Rebuffering occurs, even though the track is buffered.

The same problem occurs in the opposite direction (e.g. after step 2, it should be possible to switch to track 1 using the playlist viewer without rebuffering).

Hello World :)
Attached is a VBR WMA music file, which fails to play correctly on my “RockPod” iPod Nano.
The same file decodes perfectly using the latest ffmpeg build.
Therefore I can only assume there is something about this file which triggers a bug in the Rockbox-specific WMA decoder.
Also attached is a microphone recording of the sound which comes out of my iPod when Rockbox attempts to play the faulty WMA.

I have over 3000 WMA tracks, all encoded using an identical method, all of which will not play correctly in rock box, so if you would like any more examples, or information, please ask.

Thanks for all your help :)
(If there is any way I can help debug/update the code for the wma decoder, please let me know where to start, I understand the C source code pretty well)

~Andrew

I installed release 3.3 on my Sansa e260. 3.2 worked. On 3.3, volume controls work fine in normal playback mode, but when I switch to FM Radio, they are ignored. If I switch back to normal playback mode, I can set the volume level again, just not while listening to the radio.

As the title states the c200 v1 LCD doesn't turn on when changing the Backlight setting from Off to On. The backlight itself does turn on though. I don't know if this happens with the v2 players.

I first noticed this behavior in r24404 earlier today on my c240. I then updated the player to r24511-100204 and get the same behavior as before. I also get the same behavior in another c240 v1 player that I have which I also updated to r24511-100204. It was previously running r20698-090412 and the backlight didn't turn on when changing the backlight from off to on (I'm guessing that  FS#10130  fixed that problem) - so it happened sometime between that revision and at least as far back as r24404. It might have even carried over from  FS#10130 .

Also, just as a note, I don't notice this behavior in the February 2nd c200 simulator (r24449) - both the backlight and LCD turn on as expected. I checked my v1 Fuze (r24509) also and get normal behavior (backlight and LCD turn on), so this bug might just be limited to the c200 players.

installed rockbox and doom (freedoom) all correctly. but problem is that the navigation keys dont work when the game starts. cant move. but i can bring up pause menu by flicking hold on then off but then only up(menu button) works in addition to the center button being able to select

to reproduce:install latest build for ipod classic 5th gen 30gb
install doom from the rockbox utilities program
run doom in ipod
game loads
face at bottom of screen moves, showing it isnt frozen… cannot move

and yes i have tried configuring the keys, it doesnt work

When the battery is nearly empty and the iriver H10 is about to shutdown, the volume sometimes suddenly increases progressively, as if the volume UP button was pressed and held down, all the way up to the maximum.

This has happened to me about 3-4 times so far. Pressing the volume DOWN button somewhat counters this bug, but only for as long as the DOWN button is used - the volume keeps increasing.

This occurs with Rockbox Release 3.5 (not 3.4 as the Report Version field of the ticket says).

When the option “Auto-change directory” is enabled, my Ondio crashes at the end of the current folder’s playlist when it would have to create a new one.

The error it shows is “I09: CPUAdrEr at 09010FF8”. The address varies a bit with the actual revision, this example is with r26246 and an OndioFM backlight build (but the problem is present in plain SVN builds too). Looking at the map file shows that the crash happens in the cue_find_current_track function.

Bisecting build turned up that the error was introduced with the cuesheet rework in r21978/9 and the fix in 21982 fixed usual folder playback but not auto-change directory. It is reproducible on the Archos Recorder so I assume a general hwcodec problem.

when the FM tuner is turned on and say that you want to go to Add a Preset you cannot hear thevoice over the radio. this should be controlled where the Fm volume is turned down and the volume of the voice is turned up just like in playing regular music.

Hello.

I found that bookmarks which was automaticaly created (by the function Bookmark on Stop with set to Ask) from tagcache don’t work. Problem is in missing path to file in bmark file. I made more test and now I attach bmark where first line/bookmark is from tagcache and second line/bookmark is from files browser.
Both are on approximately same time.

I testted on Sansa c250 and Sansa Fuse2 with Rockbox r27481-100718.

Can anybody from developers focused on it, please.

Much more thanks.
Salaba

While playing doom, I can definitely read the amount of ammo, shield status, and health of my character. However, I cannot read the messages like you need the key first to open this door. Also, if you set the screen size to the maximum and turn on the heads up display the font there is also illegible.

I got no SD-Card support for my E-250 after boot into USB mode.
I plug in my powered off player into usb and only have access to internal storage.

If i plug in my player booted up there is no problem.

I am using daily build r29174-110131.

Using r30284

Initialization of the database, from scratch, on the Fuze v2, using a fresh SVN build, fails when committing.

It scans all files, gets to committing 4/9, then hangs at “building database, N files found”.

If I reboot, it tries to commit on reboot, stops at 4/9, then boots into rockbox with no database (ie it asks me to initialize if I try to view it).

Attached are my database* files.

This is a bug in post-3.9 code, as I don’t have the problem with a 3.9 release.

After upgrading my 1st generation iPod Nano from Rockbox 3.6 to 3.9 the cover art display does not seem to be working consistently.

When using a playlist the first track will always show the correct cover art, but any tracks after that will continue to show the first track's cover. This also happens if I skip forward or backward between tracks in the playlist.

If I manually select a file to play the correct cover will show, and if I manually select another track during the play-back of the first the cover art will change to the new track.

I have also tried this with current build r30334 (2011-08-20T13:14:30) with the same results.

With r30907 (and also back to at least r30809 which I tested as well) I experience unneeded mass storage accesses on my iPod nano2G. I do not see this effect on my iPod Video.

Use case:
- Create a playlist from either DB or file browser
- Let buffering finish
- Skip forward track by track
(I use mpc/mp3/aac with embedded album art.)

Effect seen: For some skips I see short flash accesses (much shorter than full rebuffering).

This only happens if dircache is off. With activated dircache this effect is gone.

As such mass storage accesses are severely impacting the battery runtime on HDD targets I hope we get this figured out before v3.10.

Hi all!
After 3.10 update I usually get my player frozen with usb plug icon if I connect it to any USB host while the player is off.
Steps to reproduce the issue:
1. Power off the iPod.
2. Plug it to Usb host. (tested with mac and Android)
3. Wait the system to boot.
4. It freezes with usb connect icon (no menu bar). Only holding Menu+Select help.

Thanks. Great firmware!

Hello!
Not very long ago I got iPod Nano 2 gen 8gb, installed rockbox and encountered this strange behavior:

After pushing and releasing Hold button player doesn't react on wheel. When I'm trying to use some other button(Menu, for example), nothing happens. After third attempt to use a button Rockbox does button context properly, showing me what I wanted to see a few clicks ago. What happens with interface after using Hold? When I return to 'Now playing' screen throughout Menu, all works fine. But right after using Hold button I can't nor increase/decrease volume, neither move in a menu list.

So, I have a Clip Zip at the moment. Been using rockbox on it since day 1, and since day one i've always had an issue: during playback, when accessing files from the SD card, the player randomly freezes. It's not always, it's not when accessing the same files or some specific characteristic shared by them, it just appears to be random. When it freezes, the LCD usually still responds to my commands (i can access menus, see the file info, even change song and it will display in the playback screen), but the actual playback doesn't, and I eventually have to hard reset it. I guess it's some kind of SD compatibility issues: I have an 8GB class 4 PNY. I know it's not the own card's problem since it worked perfectly on my Clip+ and does on my Android Cellphone.
I've been updating daily builds for this device at least once a week since I got it, and it happens with every build.

If you add a tank or a plane on a field the strenght does not increase at any time ( as expected ). E.g. place a tank on a field with a farm.

The Bug is located in superdom.c in lines 438 - 457

static int calc_strength(int colour, int x, int y) {

  int a, b, score=0;
  for (a = -1; a < 2; a++) {
      for (b = -1; b < 2; b++) {
          if ((b == 0 || a == 0) &&
              (board[x + a][y + b].colour == colour)) {
              score += 10;
              if(board[x + a][y + b].tank || board[x + a][y + b].farm) // <-- this is the BUG
                  score += 30;
              if(board[x + a][y + b].plane || board[x + a][y + b].ind) // <-- this is the BUG
                  score += 40;
              if(board[x + a][y + b].nuke)
                  score += 20;
              if(board[x + a][y + b].men)
                  score += (board[x + a][y + b].men*133/1000);
          }
      }
  }
  return score;

}

The Bug should be fixed by using this lines instead :

static int calc_strength(int colour, int x, int y) {

  int a, b, score=0;
  for (a = -1; a < 2; a++) {
      for (b = -1; b < 2; b++) {
          if ((b == 0 || a == 0) &&
              (board[x + a][y + b].colour == colour)) {
              score += 10;
              if(board[x + a][y + b].tank)
                  score += 30;
              if(board[x + a][y + b].farm)
                  score += 30;
              if(board[x + a][y + b].plane)
                  score += 40;
              if(board[x + a][y + b].ind)
                  score += 40;
              if(board[x + a][y + b].nuke)
                  score += 20;
              if(board[x + a][y + b].men)
                  score += (board[x + a][y + b].men*133/1000);
          }
      }
  }
  return score;

}

This bug is sporatic “the worst kind”, has effected a 4gb fuze+ “foolsh in IRC” and an 8gb fuze+ “DmL in IRC“, but also has been confirmed to be absent from one other 4gb fuze+

Rockboy data aborts on menu key press, when the srceen is rotated left and image is stretched across the whole srceen. Also no matter what key is mapped to the menu entry it will still fail.

It never fails when aspect ratio is maintained with scale or when not scaled at all, and never aborts when rotated right or not at all.

Only four files even mention rotate in the apps/plugins/rockboy/ directory “lcd.c menu.c rockmacros.h and sys_rockbox.c”

Sometimes the failure does not happen and reaching the menu is possible, but the rockboy option file may get written and not allow the user back into the menu later to change the rotate option back. When this happens the option file must be edited or erased to make rockboy work again normally.

I primarily use my unit for audio books while driving, but the latest build (as I write this) won't play one of the files properly. It tries to start, stuck at 0:00. Trying to seek hangs the player altogether, requiring a hard restart.

I've recreated this problem on a flaky Clip+ and an AGPTek Rocker.

The 'file' tool identifies it as: ISO Media, MP4 v2 [ISO 14496-14]

Here's what mplayer has to say (while playing it back properly):

[lavf] stream 0: audio (aac), -aid 0, -alang eng

Patch changes controls for Doom:

Forward: rec/up
Left/Right: scrollwheel (it needs a lot of scrolls for large turns, but hopefully it can be modified to work better in the future)
Back: down
Shoot/Enter (menu): select
Change weapon: left
Open: right
Esc: power

This is the game Squarebloxx. It works on Color-LCDs only because colors are an essential part of the game. I tested it in the Simulator for all the color Boxes. I also tested it on my H340.
In the game you have to mark parts of an array of tiles. If the tiles in the corners of the mark are the same color, the marked area is done. If all tiles are done the level is finished.
Please give me feedback and report bugs.

Thanks Krush

Simple patch to add RBBLver prefix + suffix to the bootloader version string. rbutil can scan the binary bootloader file to locate this string to determine the bootloader version. download.rockbox.org can now be updated to include bootloader.version files alongside the binaries (e.g. extract the bootloader version from the binary using od -S 6 | grep RBBLver )

Some improvements for voicebox on windows. Mainly an option to voice file extensions. Not perfect yet. Instead of an option to voice file extensions there are two voice files options in the hta file. Anyone know what is wrong with this?
Thanks

When the c200 is docked (as detected by the charger discrete being active), switch to line out. This was necessary for the Griffen “iTrip Auto for Sansa” adapter to produce output. I would assume this is necessary for other docking stations.

This is *NOT* a perfect patch, but it is a start and is necessary to make docking stations with audio output work.

Limitations:
* I mute the headphone output, so plugging in a non-docking charger will prevent listening via the headphones while charging. Both can be enabled… if the charger is plugged in, it probably isn’t an issue but that is what the Sansa firmware does.

* The charger/headphones detection is done only on power up. This is suboptimal, but usually “correct.” A better technique would be to hook into the charger status announcements, but I don’t have time right now.

The ARM hardware debugger via JTAG spec (EmbeddedICE) specifies a sideband channel for target↔debugger communication called DCC (Debug Communications Channel). openocd, an open-source debugger compatible with the EmbeddedICE standard, supports using this channel for textual debug messages from the target.

The attached patch implements the target side of this channel. Messages can be enabled in openocd using the “target_request debugmsgs enable” command.

WARNING: If -DDEBUG is enabled and there is no hardware debugger attached to drain the DCC buffer, debug() becomes very slow because it has to wait for the writes to time out. However, this is unlikely to happen because -DDEBUG isn’t typically enabled for target builds.

Hi all.

I have found a funny thing, which should get fixed. In set_prescaled_volume there is this call:
audiohw_set_lineout_vol(tenthdb2master(0), tenthdb2master(0));

As far as I can see this call is not needed here. So this patch removes it, but as I own only a sansa e280 I can not test this change. I hope to commit this soon.

If this call is needed… do we need it every time audio changes or only once at init?

Thanks,
AustrianCOder

This is an attempt to automate the setting of $PATH in tools/rockboxdev.sh, tools/configure and the generated Makefile.

The directory prefix of the cross compilers is stored in ~/.config/rockbox.org/RockboxCompilerPrefix. As the default path (in tools/rockboxdev.sh) is /usr/local, if that file is empty, then $PATH won’t be modified. Otherwise, the value stored inside that file will be read, the target platform type appended, and lastly /bin appended. The resulting string will be appended to $PATH.

This patch doesn’t break existing configuration. But it’s most probably incomplete, so please provide feedback on which files need to be modified as well.

This patch removes any total tracks and total discs number from the track and disc number fields in ID3v2 tags, so that track and disc numbers are displayed consistently across different tagging formats.

What happens is that if a number larger than zero can be parsed from the start of the field, then the field is terminated on the first “/” char.

Added as a patch as I don’t know if this behavior is wanted.

This patch removes the Repeat:Shuffle setting, and always reshuffles the playlist when Shuffle is set to yes and Repeat is set to All.

The rationale behind this is that a user would rarely want to shuffle the playlist the first time only and always repeat the same sequence afterwards. Rather, one would either play the playlist in order and repeat in the same order, or shuffle the playlist first and always reshuffle.

Setting combinations affected:
- Shuffle:Yes && Repeat:All

before: shuffle the playlist but repeats the same sequence
after: shuffle the playlist and reshuffles when the end is reached

- Shuffle:Yes && Repeat:Shuffle

before: shuffle the playlist and reshuffles when the end is reached
after: this combination is replaced by Shuffle:Yes && Repeat:All

- Shuffle:No && Repeat:Shuffle

before: reshuffle when the end is reached
after: rarely used combination, not available anymore

All other combinations are not affected.

The patch contains some comment fixes and some code simplification as well. We also have to handle a special case in the patch.

This patch will correct how thai vowels and tonal makers display.

Here’s a patch to have a functional usb_serial driver allowing the use of “Logf over Usb” debug function.