On Thu, Jul 3, 2008 at 8:45 AM, Joseph Smith joe@settoplinux.org wrote:
Well it looks like in the pdf presentation above they have a Serial->USB debugger. It looks like a development board though because there are a bunch of unnecessary stuff on it. I'm thinking a Serial->USB debugger is the way to go to keep the costs down, and it gives the terminal PC (serial end) more flexability. If one wanted to have it USB on both ends they could always use a USB->Serial adapter for the terminal PC (serial end). Also, this way there would be no need for any kind of a special driver for windows/linux, it would just show up as a serial communications device. Any suggestions, questions, comments?
I think I am still a bit confused about your goal.
A Net20DC is ~$90 right now.
You aren't going to be able to take some off-the-shelf USB-Serial adapter and make it into a debug device. Those adapters use fixed-function USB-Serial ICs that are cheap and small. You can't re-program the firmware to make them into debug devices. If you buy a development kit with an appropriate IC and allows you to develop the firmware, you will easily be at $90 or above.
To make a replacement, you need: Net2272 (or equivalent, Cypress, etc) ~$10 "host side" interface chip ~$5 ($5 for serial, USB would be ~10 instead) Connectors, SEEP, passives, etc $10 PCB $20
So, $50 *cost* (and the above numbers are very best-case). Then you need to assemble and test your board, develop the firmware for the USB debug Device, and possibly the firmware for the host-side interface. (Please don't try and argue less than $20 for a PCB, for your quantities, that is what it will be)
Even if you consider all of your time "free", you still are comparing $50 to $90.
If you could sell a USB debug cable for $20, it would make sense. If the Net20DC was $200, it would make sense. Otherwise, I am not so sure. Am I missing something?