Forwarded due to being sent while list was down - see also more messages to come. -------- Original Message -------- Subject: Re: [Balloon] Balloon 3 Samtec pinout - first proposal Date: Wed, 22 Jun 2005 18:44:24 +0100 From: Chris Jones To: david@itechnic.co.uk CC: 'Steve Wiseman' , balloon@balloonboard.org References: <000001c57739$35a8e6f0$0100a8c0@Alexander> David Bisset wrote: > From this I assume that the New Balloon generates 5v (for USB etc) on-board? > If not then this probably ought to be 5ish. > I certainly power the Balloon via the Samtec and not the other way round. So > I would be feeding 5vish into these pins. Good point - I'm not sure where 5V for USB is coming from, other than VDD_RAW which isn't very nice. Having said that, TCL use USB slave powered by 3.3V and it seems to work... > Can we clarify the function of the following signals: > > RUN_NAND - Do we need it? Possibly not. It was just the nearest functionally equivalent signal to what was there before, in case anyone depended on switching something on when the NAND was enabled. Unlikely, I agree. > NAND_RNB - Originally internal to Balloon2, therefore should just revert to > GPIO. This is fair enough. Can't see anyone using it. > SAMOSA_ABSENT - What does it mean, a SAMOSA device is plugged in, or is > powered and working? Why do we need it since the SAMOSA bus isn't on the > backplane (and doesn't need to be). It's the equivalent of the old SM_ABSENT signal which indicated that there's no SmartMedia card inserted. The current Samosa in the kernel uses it to decide whether to make /dev/samosa_bus available, which it does if there is no SmartMedia card inserted. Again, this is just a hangover from the previous design and might be more useful as an uncommitted GPIO. > NSLEEP - This used to be a very hardware signal that shut off the 5v > switcher, it is now connected to GPIO so cannot fulfil its original > function. Should this become GPIO or is there a real "TURN IT ALL OFF" > signal that this should be connected to. (Having said this I've never used This is still a very hardware signal that puts the ARM switcher into LDO mode - the ARM asserts it when it wants everything to be as low power as possible but still wake-up-able. That was my logic for putting it there, since the 5V switcher no longer exists. I thought it might be useful for indicating to motherboard devices or external power management that they really, really should go low-power. I guess it's become a source rather than a sink, which is awkward, but if nobody's used it, this may not matter. Chris -- Chris Jones - chris@martin-jones.com Martin-Jones Technology Ltd, makers of Solidlights 148 Catharine Street, Cambridge, CB1 3AR, UK Phone +44 (0) 1223 474968 Fax +44 (0) 870 112 3908 http://www.solidlights.co.uk/ -- Chris Jones - chris@martin-jones.com Martin-Jones Technology Ltd, makers of Solidlights 148 Catharine Street, Cambridge, CB1 3AR, UK Phone +44 (0) 1223 474968 Fax +44 (0) 870 112 3908 http://www.solidlights.co.uk/