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Smartphones and PDAs use several data storage standards, like SD (Secure Digital), MMC (Multimedia Card), Memory Stick Duo (standard developed by Sony and used in Sony Ericsson phones). The most common one is SD. Newer devices use mini- or micro SD cards, which are essentially the same but the card dimensions are very much reduced compared to original SD cards.
Mini and micro SD standard supports cards with capacity up to 2 GB. To increase the capacity, an extension of this standard called SDHC (SD High Capacity) was recently developed. This standard is used in micro SD cards as all new devices have now micro SD slot. SDHC standard supports up to 32 GB of data storage. This means that such a card can store about 50 hours of high quality music records - quite impressive! However, such cards won't work in older PDAs. The reason is not because of the standard itself (even if your device has a mini SD slot, you can use a micro SD card in it with a mini SD adaptor) but because the older versions of Windows Mobile do not support SDHC. Only Windows Mobile 6.1 and higher has an SDHC support.
Is there a solution then? Yes, there is. Exactly like in "big" computers, software issues in PDAs can be resolved by software upgrade or by driver installation. Some manufacturers offer Windows Mobile upgrade for their devices, however mostly it is not available. The solution then is to install a driver. There is an SDHC driver for Windows Mobile 5.0 / 6.0, it can be found by Googling for SDHC4WM5_pras.zip. There are, in fact, some other drivers. But this one is the most recent and works on most devices. Once you install it, your device will be able to recognize high capacity micro SD cards.
In some devices there is however an issue that the device does not see the card after going to "sleep" (power saving) mode and then waking up. This is connected with the power management configuration. When going to the sleep mode, the device cuts power supply to the card and other subsystems. On wake up, the power comes again but it takes some time. There is a default waiting time in Windows Mobile. If after that time the power does not come to the card, the system considers that the card has been taken out and cuts the power supply to it. Most SDHC cards take a little bit longer to power up, this delay may exceed the default waiting time, and then the system considers that there is no card inserted. To solve this, one has to do some registry tweaks to change the default delay times in Windows Mobile. Making changes to the Windows Registry, whether in Windows Mobile or on a PC, is a sensitive task and may result in a system crash. That's why that can be recommended only for experienced users. In any case, it is recommended to backup your device before changing the Registry. Then, even if something goes wrong, you can do hard reset and then restore the device's configuration.
There is no built-in registry editor in Windows Mobile, so you will have to download a free editor from the Web. Then make changes to the registry keys as below:
[HKEY_LOCAL_MACHINE SystemStorageManager] "PNPUnloadDelay"=dword:8196
[HKEY_LOCAL_MACHINE SystemStorageManager] "PNPWaitIODelay"=dword:8196
The first one specifies time delay, in milliseconds, between unmounting and detaching a device which is unavailable. The second one sets the time before retrying I/O operation if device was unavailable. (The default values for those keys are less than shown above but you change them to 8196 that is approximately 8 sec). If that does not help, you can disable power management for the SD memory card:
[HKEY_LOCAL_MACHINEDriversSDCARDClientDriversClassSDMemory_Class] "DisablePowerManagement"=dword:00000001
However notice that, if you do so, the SD card will be consuming power even in the sleep mode, which may result is a shorter battery life.
The above tweaks will not work in some devices because, even though all versions of Windows Mobile have those keys in the Registry, some devices do not allow changing those parameters. But even if your device looses connection to the card after going to the sleep mode, you can still use it to play music or videos because it won't go to the sleep mode then. When connection to the card is lost after wake up, it is sufficient to re-insert the card, and then it can be used until device goes to the sleep mode again.
Leonid Sinichkin is an IT specialist and programmer in the field of system and process automation. He is also an experienced user of smartphones and PDAs. Learn how to make Skype calls from mobile phone.
