On Wed, Mar 7, 2012 at 9:53 AM, Adam Wang <[email protected]> wrote: > > > On Wed, Mar 7, 2012 at 6:39 AM, Werner Almesberger <[email protected] > > wrote: > >> - J1, J2: I found a direct data sheet link that works at least for now: >> http://www.scpre.com.tw/Download.aspx?oid=1361 > > >> Seems that pins 4 and 5 are swapped. In M1rc3, the were connected to >> each other so it didn't matter. >> > > yes, i found that vendor changed their pin assignments number when I > added/checked for insertion/removal, but the footprint/mechanical location > in design files are correct to the same as rc3. If i fix this, means that > we also need to fix footprint library but will uncorresponded to previous > rc3 assignment in schematic. > > >> >> - C2, C6: Table 18 on page 33 of the WM9707 data sheet recommends >> C2 (their C20) = 10 uF and C6 (their C18) = 1 uF. We have C2 = 3.3 uF >> and C6 = 2.2 uF. >> >> While it seems that making C6 bigger is fine, I'd be less sure about >> C2. It appears that, at least at 0805, 10 uF is more common anyway. >> >> > (C2/C6) was kept to the same as previous codec lm4550b, since in rc3's > design verification stage we agreed to the performance of audio noise after > dropping wm9707 codec directly. Yes, If we'd like to follow wm9707's > recommended parts (C2 -> 10uF/0805) which is also good to me. > > >> Also, C2 and C6 are drawn as polarized, which doesn't seem to be >> necessary. Or did you do this to make it easier to tell GND from >> non-GND pins on the PCB ? >> >> > (C6 polarized) This can be unpolarized if we follow wm9707. > > >> - R1: a remnant from the previous codec chip ? >> > > This can be removed directly since it followed with lm4550b codec: > http://www.national.com/ds/LM/LM4550B.pdf > also according to page 14 of > http://www.ti.com/lit/an/snoa477c/snoa477c.pdf > 10 K ohm pull-up is not needed or recommended for the LM4550B. > >
To them above, i temporarily edited into latest one: http://downloads.qi-hardware.com/hardware/milkymist_one/sch/tmp/MILKYMISTONE.pdf
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