Procyon, the biggest of teho Lab’s Cortex M3 development boards, is now available for $72. Brian has been posting development updates in the forum, it’s great to see this board in production:
It has a massive 16 MB SDRAM, the ability to host USB devices (or be a USB device), Ethernet to get connected over a network, and a microSD card slot for storing data non-volatility. You can execute code out of the SDRAM if you wish (though it is much slower that way). It is a great board for anything short of an OS. There is no MMU on Cortex M3 parts so a true Linux port is not possible (as far as we know), but uClinux could be ported if someone wants to try that or another RTOS such as FreeRTOS.
…Great choice on the USB connector…
How are users supposed to use the USB peripheral in device mode?!?!?
Perhaps a Micro USB A/B connector would have been more appropriate…
As noted in the Doc’s section using it as a USB device is easily done with a cheap gender changer like this one: http://www.monoprice.com/products/product.asp?c_id=103&cp_id=10314&cs_id=1031401&p_id=4817&seq=1&format=2
The connector is more robust for the main design use of hosting devices rather than being a device. Also using a Micro A/B with a regular USB Female device also requires an adapter. (I supply one with Eridani) this adapter often has higher contact resistance than you might wish to power something that draws 1 A and thus my choice to use a Female and let the lower power draw be though an adapter.
Let me make that more clear. If you choose mini or micro A/B you can get a cable for device use. If you want to host a device such as a full size USB male such as a USB key, keyboard, mouse, hard disc etc. You have to use an adapter.
The way I have designed the board you don’t need an adapter to host these devices but do need one to be a device. Either choice requires an adapter for some applications.
Because things like USB hard drives violate USB spec and often draw more than 500 mA it is better to avoid the USB adapter for the hosting rather than the device, because the extra contacts can be flaky or increase contact resistance. Meanwhile the board should draw less than 500 mA so it will be less of an issue to have it use an adapter to be a device.
I think it is a very sensible design choice, but no matter what design choice you make I have found some will think something else is better. That is the nature of a design choice after all.
If you require a OTG micro A/B you can purchase a LM3S9B9x board from Ti without the SDRAM or microSD socket for 28 dollars more than my board.