Podule updates

It seems the Castle USB podule is based around the

TransDimension TDUHC 124B

Any ideas on what is required to drive it?

Not sure. You mean the RiscPC Podule from Castle?
I have one and I have the driver but I not have a working RiscPC. How can I help? Should I borrow it or sale you? ;-) Or need you a info?

Data sheet and some mentions of it in conjunction with NetBSD.

It’s not an OHCI or UHCI device, so probably it means taking OHCIDriver, ripping out the OHCI stuff, and registering your own device with USBDriver instead. Data sheet is only 70 pages and it doesn’t look too complex compared with other USB controllers, but the devil will be in what they forgot to tell you. There’s an OHCI or UHCI personality layer, but I suspect those aren’t available or under a permissive licence.

See also this thread

Ref your ptr ‘Data sheet’
Page 8

Supports OHCI/UHCI compliant USB host stack

It seems that someone has got the RO5? SCSI modules working with the Castle USB Podule RO4.xx.
Seems working with 8GB USB stick.

Is there any software source of the Castle USB Podule?

Supports OHCI/UHCI compliant USB host stack

If you read the section on p10 it says:

2.9 About UHCI and OHCI
UHC124 is fully compliant with USB Specification 2.0 (for full speed and low speed operation).
However, it is not UHCI/OHCI because it is not intended for the PCI bus. OEMs may develop
or license, a HCD providing a software interface that appear to the rest of the USB host stack as
if there were a UHCI or an OHCI compliant host controller.
In Fig. 6, a carefully crafted USB host engine “steals” a small fraction of the MCU’s time, to
support UHCI/OHCI operation. The UHCI support for the UHC124 is readily available from
TransDimension. Please contact sales@transdimension.com for OCHI support.

In other words, pay us extra to get UHCI support, and we haven’t written OHCI yet.

There’s also a driver library but no licence to modify or distribute it.

I’m quite surprised that someone has got the RO5 SCSISoftUSB almost-working on the podule – would have thought too many things have changed.

I don’t think I’ve seen any source of the podule USB code anywhere, BICBW. You could ask John Ballance.

Castle did pass on the source for their USB podule to some one. IIRC they spent some time on it but didn’t get far and decided other RISC OS work was more appealing/worthwhile. I don’t think many Castle USB podules are in use now a days. With RISC OS USB programmers not twiddling their thumbs is it worth pursuing?

Looking at the datasheet it looks nothing like OHCI it looks relatively simple – if simple and USB can be used in the same sentence. Its probably just as easy/difficult to write a controller module from scratch rather than try and emulate OHCI and some how have it recognised by the OHCIDriver. Most of writing a controller driver is writing the methods that go in usbd_bus_methods and usbd_pipe_methods (Netbsd.dev.usb.h.usbdvar). You need 1 set of usbd_pipe_methods for each usb transfer types (bulk interrupt etc.)

So on this device you can have up to 16 transactions in a millisec. The high level interface supplies a block of memory to transfer and a call back to be called when the transfer is complete. You queue these requests and feed them in to the device so that the device is ready to send every ms you are informed when complete and go through the completed transactions calling the callbacks. You keep a queue for each transfer type (bulk isochronous etc) and feed the device in the correct order – there are rules for this in the USB spec.

It would be an interesting ‘my first controller’ project.

The RISC OS fudge icing on top of the BSD interface is probably harder to understand.

Would it be possible for a Bounty to be had for a RO5 updated USB Podule drivers Castle/Simtec?
Even better if it could be made to work with RO4 etc.