USB Host Capability
Micro-Robotics has developed a USB host driver that allows you to plug in USB Flash Drives and other Mass Storge Devices. The new Application Board 3 incorporates a USB Host interface.
Summary of Features
- Hardware : The USB Host interface is based on the MAX3421E device. The interface circuit is quite simple.
- VM2 channels used : The interface uses SPI Bus 2, which it shares transparently with the Ethernet and Memory Card (SD/SDHC) interfaces.
- Speed : The hardware supports USB 2.0 full speed but not high speed, so the raw data rate is 12 Mbits/sec.
- One device only : we do not support USB hubs, so the memory device must be connected directly to the USB socket
- Devices supported : we have tested file system read/write operation on several different types of USB Flash drive, SD card holder and multipurpose card reader.
- File Systems Supported : FAT and FAT32 file systems are supported.
Venom Interface : A file system object for a USB device is created
by code like this:
MAKE usbfs filesystem("USB")
After that, use of the file system is very similar to memory cards.