Decide USB Host to read USB Flash Drive

(This message was transferred over from our old forum)
Posted August 19, 2015
By Todd DeBoer
[hr]
On 9/13/10 tom.abcd asked, On 9/13/10 tom.abcd asked, “Is there a a simple demo that just shows the USB host supporting a USB stick (Mass storage device) with a Fat 32 file system.

I am looking for a solution so I can be a USB host on my STM32F105 processor and be able to read files from a USB flash drive. Looking at the LPC2148 demo it appeared to have lots of stuff in it including USB host and mass storage but I am looking for a simpler example to start my port from.

Also does the Fat files system support Fat32?

Any guess on how much work doing a port will be? (I have been using the ST processor and Crossworks for a while but have not use the USB yet.). “Why is FAT32 only supported up to 2 Gig devices? I know that some of my customers could have 4 or 8 GB sticks. Any idea when support for large devices will be added?

Are there any support options in the porting process? (I have also sent this USB / fat question via your web page support but I used my work email address. )

I compiled one of the Crossworks 2 LPC2478 sample apps and it used 445K flash, about 16 kb sram, 16 kb usb ram, 16 kb ethernet ram and 6.8 MB of SDram.

I realize this demo has lots of things I do not need so any guess how much space a simple app that is just the USB host stack and file system will take? (I guess I am looking for something in the 70 KB flash and say 30KB of ram)

I looked through some of the config files but did not easily see how to pair the sample app down to just this.
I saw the config.h file but it seemed most of the items were set to 0 which I assumed means do not compile in.

#ifndef UEZ_ENABLE_BACKLIGHT
#define UEZ_ENABLE_BACKLIGHT 0
#endif

I then found two platform_config.h were most of the defines were set to 1. I then searched through the code and h files but did not see where any of the defines were used.

#ifndef UEZ_ENABLE_DAC
#define UEZ_ENABLE_DAC UEZ_ENABLE_DAC
#endif

#ifndef UEZ_ENABLE_FILE_SYSTEM
#define UEZ_ENABLE_FILE_SYSTEM 1
#endif

So at this point I am looking for a simpler example app to start with and then get that ported over and running on my board. “
[hr]
(Follow up post)

Answered:

There is a 2 Gig bug limit has been fixed and will be in the next release (should be end of this month).

The demo does have alot, especially about 220K of graphics that you may not need.

In uEZ v1.05, you can go to Config_App.h and set UEZ_ENABLE_TCPIP_STACK to 0 and turn off the UEZ_ENABLE_USB_DEVICE_STACK to 0. Then in MainMenu.c, there is a global variable called mainmenu_entries that declares which icons to show on the main screen. If you want to turn off most of the features, just comment out all these lines and leave just { 0 }. This cuts down the build to about 197K (debug/unoptimized), but still has the graphic library, touchscreen, etc. etc. still active. More can be turned off if need be.

Look at the Config_Platform.h for your system to determine what is enabled/disabled. Config_App.h overrides Config_Platform.h, so you can make customizations there.