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Harald Welte laforge at gnumonks.orgOn Sun, May 08, 2011 at 05:00:59PM +0200, Kevin Redon wrote: > Hi > > The corrections have been applied. I hope I did not forget anything. thanks a lot. > The main changes : > - reset is a jumper just to be precies: it's the TEST pin, not RESET (schematics is ok!) > - bootloader switch added see my comment from the last mail > - 100k resistors used (instead of 4.7k, I hope it does not break anything) yes, it should work. and if we run into problems, it's very easy to solder different resistors to the same footprint. > - jack connector added (for the debug) > - WP from flash connected great. Does the SAM7 have an internal pull-down on nWP? If not, we should add one, just to be sure the power-up default state is LOW. > - USB voltage regulator TPS73633 used (lower capacitance) Ok, let's try that one. > - USB buffer used instead of the openPCB solution (thus no pull-up and > reset connection). saves space and complexity I am not familiar with USB buffers? How do they work? I couldn't find a data sheet for USBBUF02 or USBBUF02W6. Also, I don't see how this solves the problem, sorry. Some more explanation: When the AT91SAM7 is reset (software-reset or hardware-reset), it needs to generate a USB bus reset in order to tell the host PC to re-enumerate. This is required as the SAM7 has no information about the USB protocol state before the ARM CPU was reset. The other reason is: When we switch from DFU into normal mode (or the other way around), we again need to be able to issue a USB reset from software (via GPIO) and ask the host to re-enumerate. This is required as we expose different interface/configuration descriptors depending on DFU / normal mode. So I don't really see a choice but to have a software-controlled USB reset option. Once again, we know that this part is working in OpenPCD 0.4 (we had a couple of earlier versions, and they all had some shortcomings). It's really useful to have both the nRESET as well as the GPIO controlled usb-pullup (called UDP_PUP) in OpenPCD. If we don't do this properly, we will have to disconnect/reconnect the device from USB very often. Doing this from software is much easier and fail-proof. > - QS3244 instead of QS3245 used, I/O and other pins are controlled > separately great. -- - Harald Welte <laforge at gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)