Hi Joerg, To let M1 have awareness of plugging audio line in/out connector, followings are proposed idea and combined earlier suggestions from you. A latest draft schematic: http://downloads.qi-hardware.com/hardware/milkymist_one/sch/tmp/MILKYMISTONE.pdf line-out: 1.) add one pullup 100K Ohm R233 to 3.3V and connects to J2:3 pin, 2.) name a new net LINEOUT_DET and connects to both J2:3 and fpga. so this detective pin is under Normal = Low (0.303V), Plug-in = High level (3.3V) line-in: 1.) add one pullup 100K Ohm R25 to 3.3V and connects to J1:3 pin, 2.) name a new net LINEIN_DET and connects to both J1:3 and fpga, 3.) add back R23, R24 6.8K Ohm in previous version and connects them to AUDIO_AGND. So it's under Normal = Low (0.395V), Plug-in = High (3.3V) level
VIL(V, max) for low detection, according to table 9 on page 10 of http://www.xilinx.com/support/documentation/data_sheets/ds162.pdf which is safe. On Wed, Feb 8, 2012 at 5:33 AM, Joerg Reisenweber <[email protected]>wrote: > Hi Adam, > > Yes, this looks pretty decent, the schematics (p.1) as well as the selected > varistor which is a nice component and perfectly suited to replace the > 47pF. > :-) > > yup, applied. > As there's always sth to improve :-) I suggest: > cut J1:3<->2, connect J1:3<->1 > cut J1:5<->4, connect J1:5<->1 > rationale: connect unused input to GND -> less noise > changed on J1:5, but also applied plug detection on J1:3 as above. > > cut connection and insert a 100R, from joint C19*R17 <-100R-> J2:2,3 > cut connection and insert a 100R, from joint C21*R18 <-100R-> J2:4,5 > Rationale: some protection for LineOut amp / internal clamp diodes there > > 100R added, and there are no clamping diodes in the fpga. I edited two varistors in advance there line-out path, how do you think ? > > consider 2pin with jumper to GND for TP50 > rationale: again noise of unused input > limited to present crawl space around U1 and new proposed U-Shaped expansion board coming up which will at exactly the upper area of U1 too. We'd just keep those footprints of DC block caps. instead of 2pin headers or test points. Hopefully comments feedback when you're available. Thanks. :) - adam
_______________________________________________ http://lists.milkymist.org/listinfo.cgi/devel-milkymist.org IRC: #milkymist@Freenode
