SDhc Cards

mikealder · Posted: Fri May 02, 2008 7:25 am Post subject:

The bug/ fault is clearly within the TomTom and for once it is not the Home software to blame.
If the 8GB card cannot be seen / used when fitted within the TomTom by Windows Explorer, but can be seen/ used by Windows Explorer when fitted within a compliant card reader - it is the TomTom device or software on the TomTom device at fault.

Your findings are the same as mine with the 8GB card and what works/ what doesn't, you will find exactly the same scenario if you do get a 16GB card - Mike

GilbertQC · Occasional Visitor Joined: Jan 16, 2008 Posts: 4

@saikee,

Can TT system write to the SDHC card at addresses higher than 4GB such as doing screen dumps? I know that on my SDHC of 4GB, using a ONE XL-S, I can write to addresses higher than 2GB with screen dumps. I was wondering if there was a lmitation of 4GB from TT system or if it can address over that limit?

F2 · Posted: Sat May 03, 2008 7:31 pm Post subject:

saikee · Occasional Visitor Joined: Apr 30, 2008 Posts: 21

Sorry I have been busy and didn't return to the forum for a few days.

Now here is my latest situation.

I now have 2 8Gb and 1 4Gb SDHC cards for my TT 920.

As I have reported with the PC software I could see the 4Gb when it is inside TT. With the 8Gb the PC cannot detect its presence inside TT.

When the 8Gb SDHC cards are outside the TT and connected to the PC via a USB card reader everything is normal. I can read and write on the 8Gb SDHC card.

Most importantly the 8Gb SDHC cards when re-inserted into TT everything works too. I have not used TT to wrote on the 8Gb SDHC card. Don't know how yet as I am new to TT but my SDHC card has a huge MP3 collection, the relocated North American maps and a good collection of photos, filling up the space to 7.3Gb leaving only 194Gb free space in the 8Gb storage. So far TT can access all the data.

Thus if TT can read beyond 4Gb then I expect it can write on it too because the SDHC cards are in Fat32 format and technically capacity over 1TB would not be a problem. The limitation of a Fat32 partition is no single file can be larger than 4Gb. That to me is the PC standard. Since TT uses it then its operating system should be able to cope with it too.

TT920 has a FM transmission facility and the sound quality is quite good. I am using TT to play MP3 music while it is doing the Sat Nav job, all the TT audio signals come through the car's FM channel.

mikealder · Posted: Sat May 17, 2008 7:32 pm Post subject:

You could try writing to the SDHC card by selecting the American Map (which is on the SDHC from what you have written), create a favourite then switch off the device this action forces the device to write to the card.
Power it back up again and can you still see/ use the American Map and the Music stored on the card?

Don't do the above though unless you have the time available to format and re-load the SDHC card when/ if it doesn't work post saving the favourite, at the very least make sure you have a full backup of all the data on the card before trying it - Mike

GilbertQC · Occasional Visitor Joined: Jan 16, 2008 Posts: 4

I think the best way to test the writing capability of the TT system is to do a screen dump. When your card is pretty much filled, there is a good probablity the address it will write to is in the upper range of the card. If you can read back the screen dump, it is fair to assume the system can write to these higher memory addresses.

saikee · Occasional Visitor Joined: Apr 30, 2008 Posts: 21

Just an update.

I did what mikealder suggested to test if I could write on the 8Gb and the answer is yes. I got a favourite recorded in the Canada map which is stored only in the 8Gb card.

The problem reported by JaTe is more to do with the file handling of MP3. I ripped the music from all the CD from the house and have over 9Gb of them. The mp3 format actually stores all the attributes and there is no need to mess around with the directory names as each one was self-generated. I therefore did not have JaTe's problem with multi names.

-----------------------------------------------

Personally I suspect the problems of the read/write problem above 4Gb is a TomTom bug. In the PC standard the published maximum capacity of the Fat32 filing system is 2047Gb for both Type b and Type c (LBA mode). If the TomTom software is designed to read/write a Fat32 partition then it should have the addressability to read beyond 4Gb. So far some TomTom programs show it is the case while the others couldn't do it.

I had Fat32 partitions in hard disks as large as 500Gb before working perfectly.

saikee · Occasional Visitor Joined: Apr 30, 2008 Posts: 21

JaTe,

Once ripped my MP3 collection is playable in any MP3 player, any PC, any operating system and now on TomTom. It is 100% maintenance free.

Wish I could do the same to the Sat Nav maps.

GilbertQC · Occasional Visitor Joined: Jan 16, 2008 Posts: 4

saikee · Occasional Visitor Joined: Apr 30, 2008 Posts: 21

GilbertQC,

I only stated any MP3 player.

MP3 is a filing standard and doesn't get changed from media to media.

The MP3 songs I ripped were from a free Internet program that can recognised the CD title and the names of every track. Once stored into a hard disk I just copied the content into the MP3 players whenever I want to play them.

In the case of TomTom I just use the PC to write the MP3 folder onto a 8Gb SDHC card. When I ask TT920 to play them it immediately recognised them and increased the database of its audio track, allowing me to select from albums or artists etc.

Whenever I load a Linux distro and want to test its sound capability I just present it with the MP3 folder I ripped in a MS Windows. I have to say there have been more than 100 Linux I tried and none of them missed a beat. Thus my MP3 orginally stored in a ntfs partition can go into any Fat16, Fat32, Ext3, Reserfs or other partition I don't even know what it is and would work. My HP PDA needs to convert my MP3 data into its own format but the same songs still play at the end.

If one purchases a hardware that states it can handle MP3 files then I expect it can play my MP3 collection. Other formats are a different matter.

	PocketGPS
	Web