From a673d621767f7593763b4c57294a18b49b35811a Mon Sep 17 00:00:00 2001 From: Werner Almesberger Date: Tue, 27 Dec 2011 03:58:42 -0300 Subject: [PATCH] m1rc3/usbpwr/: added tests with an unfriendly capacitative load --- m1rc3/usbpwr/README2 | 30 +++++++++++++++++++++++++ m1rc3/usbpwr/usb-icreativ-50us-psu.png | Bin 0 -> 4529 bytes m1rc3/usbpwr/usb-icreativ-50us.png | Bin 0 -> 4628 bytes 3 files changed, 30 insertions(+) create mode 100644 m1rc3/usbpwr/README2 create mode 100644 m1rc3/usbpwr/usb-icreativ-50us-psu.png create mode 100644 m1rc3/usbpwr/usb-icreativ-50us.png diff --git a/m1rc3/usbpwr/README2 b/m1rc3/usbpwr/README2 new file mode 100644 index 0000000..665780b --- /dev/null +++ b/m1rc3/usbpwr/README2 @@ -0,0 +1,30 @@ +M1pre-rc4 vs. capacitative USB load +=================================== + +This is a test of how the current-limiting USB power switch in +M1pre-rc4 handles a "nasty" capacitative USB load. The worst load +identified in previous tests with an M1rc3 with altered reset +logic (but no current-limiter) [1] was an iCon i-Creativ. + +[1] http://lists.milkymist.org/pipermail/devel-milkymist.org/2011-December/002488.html + +The M1 was set up in the nominal 5.0 V configuration described in +README, which results in a supply voltage that's about 200 mV +below what M1 should normally receive: + +Source Input J21/J3 +------- --------------- --------------- +5.00 4.81/4.86/4.90 4.47/4.62/4.72 + +The worst drop of the 5 V rail that could be observed in about a +dozen hotplug tries was about 450 mV [2]. Note that the probe used +in these measurements has a linear error that cause readings to be +about 2-3% low (~100 mV in this case), i.e., the lowest voltage +was still about 200 mV above the threshold of the reset chip. + +[2] usb-icreativ-50us.png + +The tests above were done with a lab power supply that has very +fast current limiting. A test with a 5 V switching power supply +similar to the one shipped with M1 showed a reduced drop [3] of +only about 350 mV. diff --git a/m1rc3/usbpwr/usb-icreativ-50us-psu.png b/m1rc3/usbpwr/usb-icreativ-50us-psu.png new file mode 100644 index 0000000000000000000000000000000000000000..deccbcb3add1cb4aa11952035b2e70acb1911499 GIT binary patch literal 4529 zcmb_gXHXMdv!;X+ATPyGqz17Nii9Re4@gxah8B7i5Rjtu4pKuC1tf-!BqGfKf^>z@ zJ1D)V^xi?5+<0g1%)LME%s2CWKc3y4-F;?u_M9_&&WY1QXoBcC>Bz{)K-yaOkYr@! zDkOW2mVzYBDd@kF6wpJ<?H6R1GokJt#w0T;ZqJ+zG?MM89sS0)UfC8Ua{e^QZec`lf8JYRXL)&GZ{&53;KP&i^NA|j!0zZ1XDRVsNp63(yeH-- zphB+J9#`WIg83b(G@)OL%sAIOLuHe{S{etigJn1Ii+DT+(z^I8+gvL&in zv(>wK_?=__&+-8L%*;^HuD1tY+t|J@W#)g(WMn*?_7#m>@7xwPSfZt*lEZZ1X@*v#e263^S)eSwiX|5T?zT18qxH*6`AKg4W z+@9jof7VblHa0b)FW{Yo>qR_UqH`!1WSPsLv&AfyO-*G5PD(1ydg$j(_D{qD$9vlp znAc$thJpfbDR;wO#5#iST+>(86bnaz|tCA4C4fEv;6xmLUNY z4u(Bzzu8VQErpGY%i0%f&A*s^`Sum3dRVO|{Ge2v^)((6>)kw8Hg=qxY-$+(f>0M6 zyG`xey%~^rCl8ZS5E?!AwrRp@9rV$8!F{!mcbr4N4QTAOq>DjUBV?R$qvVs(=4Zw` zN2lFpjCKjN=H{SKAZ#i8iRu`?mnS;YQowKR;%s}aYG?0UM5dxFRTL{GeKluqoM&RD zwk;lqZU_yjb9{00VCwHetK2ia`l!!f{%t!es_h($8w+7~QRQ8Ot%!OV` zuynhB@<%txq}kM0&QS1jc1LC?OEP*n=v2zE*c7L5 z@!-$s^D!1i*DQYr&5`Bb)X$ghX_FEmMs3z8EKbNLj7wqJyA-JFZ+W|%uZD4>PzxO? z|4JUk)$w5~eNI^k$%zA6#K3&iX#?oX3a~_LeZ+3KO|Zm7lB>Z!XVJ|B|HctWFy}4*h)3(;Gv}G6B zmV$bAdG&CO=ChTCtzs2)Q-HANho-|04!K_zCTM9G@y+@5ClK?2pwfA$eUUYqcU4tQxU@J8gS0H&^Lx(ojHikc}88|O_i5QPUkZ-b9y?eDh8E$b)MK(A|+Vp z!C&-r0(m1Pdsw2PjmFDnR~k%SA-8Tl{^;a0Gdur44N3*E9_%}cHC~cN9tIo6q@XUa zYk}8|n7cAjH}B*iWT%V{M0d$Q^k)hdg>iASMnY?|R!0mDE%Se4f77mCA+-S98Dtis(-S?ocSzP7Imo-C2*!rJOh$=m*ZmNV3qUe$gtq z!9=9cW1yhcV-O&m${f;?eo$pv-)?5K>xBi)l>6A2`Vg*88)7Arx^ykk^#W&OraRSdGurdbW+v;> z8#65f4g?z%1D45iuVFQ8b=P#6btZeG)*K|`z8J1;%?-oTWETo~=D#C&tr^n~!`Y!W zPZaKs*z0;Xj73!-8;=v;nj0%zu8?4*Lm(?|7vroKv_;{;Y z4;Q6Ak{bxhJST3=ui#6HC5t=CmndK6L)b#JV-=EELA98BANv4#@>c-#7L_*A5|60; zdE=PJ<1{pF;b_)=WzKsjnTkZsYPJQ6rB~Sr4U)|(RP_yz%(jdsSbWoG#6I*%h*&VU<0_)m;Rqiv z;Z>f!-`z2?-+|R`wkS8;ILOLoUl@jZM_c=AE%+0?#-u^5)|ZGNtN8tOjJB`&0W8UZ zgL=&U;p&#>MCs36TtDS%{BTDAZ$`R)_@C34@}L0nyK2=P*Vtier7CB~!9vcBg~I=E zbvb2>Y0(TVUL-my@c_&*b|IeI=8;V`f=krRpT}@e4O^a$_HsjL+u3ZPj1xn3tCq-k zN^cDjhw!d)(G?4jrvb{IUgwS0s;hIXuA}4AE*-LaX-f!OE|)WAD^Xp`vrbnK`@lyf zlMnbw`xN28oDyc0UEUtM_2+#^q}!c>#1-5}N3p7pstdv&Xdd|t+rLP`qj77!acLOH zT8BBT-cU+h+RV_a3~F~yT(O)!eYaO{R)A^EYuU?+j@v@;qZjU{T36E$BrK)oyRR4S zHHqiU8SI5z#SRHY#Z=dEPUrR}RYax1OLmUZ4q%c`$3*=cW}<#IT~Eu~ZQujs%Tzr0 zQZEEc%kVuc()CXk1^XyX9qkXonL-#_x}qC&6UZv1F4iMY>T3f&{fiJU^x~2}7OlR85gU6!Q4xJ-KDE*qC7J@rY-3!|LR2YrImeQ?oSFPSd;FC+Jyk zAzt3wSi>Q-n}I0M#h4G2o^rf~0p4h1-q~^ub-mBM;f!s&_Z|GONzd=6`-^)WeldOF z9xh(fenMs`RB#br+!OaJ#Tr4!^%K(-ZOqmu7j`m8}| z$VT^zg(Ear%?&_E65vd!D88?|sVMf2eIssESuQWgG16G5(p030Mr;5;fIud@9-0bDi%r)m2{$}k1JtZ+&1`^h;f zJ2?ho^jM;=G<$1%&ixnUs2*4N^SQ-Weu#-5U`i@kDwYQTJaMO(4Nf>qx%4g*t)$(QDjG~*)r^Pyn1T1o^Pkie2C=26 zk0kTmS#=)*Q_M2I3%rf-H7LGObL<{0LaO!>cS>u^sw;YNBkLPcV94Z;r2ZRwBhm>t znY++_Ds7w66PmR%7p7*SDmw$N()LSiNIh4do@b$9<*>@msi7vc(_EcGvVNOV0wH2I zi)3CupU~5Bap8#e-x>Q%Bm9o|> zNjKyIFG#nW0ftT33|)}#L#Y3ZHkAScE3bqdW2mXZ&{TKYP-IRH7OATiP7lGjU(i9T122^MDi z7qp~)p&|dNNXB^MrQuB<<3>^)WNZAfRD=Aq94g{}kw9FV0}BwUu-9U#a=9W)KiD}q1^ zosAlGbE}k;nFudP$AFf|!&c>spJ$B#8Bos5V=zD$nO-*)+OUCmH6MEuJZ4&}}S9n;=_cVNBA~KHC^Y~SON~Hhw z!t0+S4v_iSd@B4R>_&6FL3ZInQ(|iKs-iLX1y=PJrZu%(%rsSqIuMpru&%u6oFVHV z_E2a*@bh~N(o(u1_;EtAyH$4;{gu}@Es$?TaP~U>j8ru`mcht#AxCCeGh^d;DYj~F zMbbkCH6XIvWuwn+Bze*ZYde#Fs^hONBfe%V$x6GwaKH4Z7y6K^Z*^7SK}srJO*b>} z^EkVOra>cyL3m@zx!@<|OTQtfqWs|&g*IeaH9OQ~yt_}T`8f@;d*0bBe<3q$@i_S4 z9BlT(vS=`t*wM`+vC&7zgVWKSti(nZ_MY=s6y}ILG8JzNI(uFZeLUjQNWX3!Lj7!d z+rb8GI;_%nFS*sVO|Yu?dr++K)u<&ykLZ&g)@|HzgGtq{xp?*l5QXe!17b(5{BQT~ zgwzXof+wFRv|h4v-M-8qP<3?3y5bzb|va#&oe~n zpFEkVqy*%VbllJ`n#+R57ul&tp=w4qN}f+i;68twSxxOz2+~k6E^Uma*)02}&pJ*fdB`0v(-3{MX z`#;bcu?+4)LYy^Y$lFriW{iyJEI+T7C)Kb*t$f4hVy?<47+;VSuDdAO+hQ{KOqb-t z#lR^@v{%Tl^Rvx-1aY_HWn)uo#hu$b=eFR9r8g+$?qWue=M!fu(cqZ2swA6se*Rt`xo?U`K zl~hl&k;waf3deiI5VV0^fEm(lU#dCV<9TIQTRHEIulh5JL;R~XEru)2kM3W@E)y4j z-?2+G9x|wp+{cs`LLarR9IaopH+QtZS<4|RF3;t26j-k$V&i2)-2QsuWg?Osm`Gv8 z`UD()AdZnG+rw>nw$E3I%qL2->(Jm0mEYS1{<7Zkh?=|t=)$q@q2Na4>ce+vne5f< zlVCV^jRSUXs-ecT(?3X?rSsvz?o$KK$^|=lajH7d9LfG9UsLEq zj`hl`{1}pe>eMbo<%S3y2cYo*;nqooq#r;cy%}c7-$xEs!Yl(uM_@O2&NT_YrT>sZ zL*a4vb2=tqU%Xen9~BN=`Alud?G3W@W2ox3NUq3NW>rJ={fxl0wRQMS-H_*~nJ;vp z+bJO8v+(ND{5ltQ5wNi0$V!n;_d^s-}7UG~5e6eDkq05ZpzS>*zH}VTrsTv%C_l zIdp|jsm@)uBZ$2{=mZqn;5{-FV8ZimzQ8J)h0SwbX^TdIn-=A!PA{R~{FwPebjlLb5@UDf6>nYIqSc1vR1LQgJ(x|~Ys zaow=}!8{S6*K^c5=CPf?92A)Z`8~0m=06pWze$Kt@?J^h_C}otr9|&Fmy&mBk*zh&>mD#RsQJ^ak!;1pm6SFRC(d8WZ$&fB zAG&a%7@j(#Dd}8j|iJ?zhl5L#!47EcfA0g zTbNlc82P@s>!5ayll`izJ7Lg5KV(~iko9og;>9><*bP~KI}OLy zFsYgv85nc?%N*o9!})5`SguXP?`|f96iVQHq4mz2wVgg&GKI59^L%L!JCsoC63qI< zk9B5?yf$i2sfGVcCt4d0S|uOl95rMT&E~ErXl)4Xp}ZB$W~`e86(U9TV|q5UlD~V% z4)=N%TbAPF)+9?bXmI8MfJey{#mBG+b?4Bi0~h|q|on1 z1+qETd8R5L*NhNL2;xCNseciQK9ob&SW5BHegIT2m}ZOf^ypmm+y}djgw&A`SAKfS zW;)BVx2`-y*JzaBGH4hH0=GmfDcIbn$28AB_^5Z>=;h%?*4Q>?PaLqjHb__yqxx~(bmj1$D@LN@}J3?SiR8MyFg zD-XV&4y~qzE~U@6ET3z;VJ<>iJ)K2D-F`wC7j=daOEp4Ye%@>nw%Ngp4-E~?tOVpE z9BT2?FZXRW%_QlaWhNsf$Gt9W7CxuJO5hr^Q zdoA!#oz955{I{tmG>+&IFbtqOiz4N|M8oA`jtm_dB|eV+ek`aBs1XQD`h4&?Nm~a7 zO7pKeXa5GzjPuek5A)G!t=e(U0C@(R1_EZTZZGII3HpXDw>`7g2&RhJu1p=#>-xPN z)XbXldk!89+t6ji#kPDmsxXCo*AMf|T%cx}x0@qi)68B@XlxGFuy7uA*3#5#{E7Js zm*iWllZ(t42ziM+${5V}`V`BN!S&(U0C=8b_{oT@wUqCkk6?!tcM1Q!A#A(h4_JD4 zfztr%9Ur&N>O+h)LZQ+fJ4ngpWZju4n%r_lKbVPo#uAly;EQckyeW=hP0S5(XPtfTk;7A8#xT*zhiy`jvVV zCt&MMe~BN~SR?=JhitU|L==l`s`x|caG38l%VNoQWFWAJo-Kw>F)*{g7`Kaub_R-+ zKy87tpM;yW7ui_kSYKw`?FboGD(AxqW~$wiP$5Sd$d(Fkf*4Xx?!7Z22%#t5=$MWH z?sQDMI#+E|m)UO}hKv-ZwL*`Yw!%iliSt1-PS<6QI|pf}&CH{_f{nMl!BsaLVL>>G za>wJf&NFkU*snjHwta7P$9YGtoQQb-&Ue4EO{pNR;_?#6*9JvrzwO5?_%)>kYM0h3 z*aGF`!J)cZCm>j8oB5%VC^7heF>lNbw94so3spI(wdMD=h3dgO3g3L2c#!!7z>xl= zHt;wob)6DXCdX>*^n}?<2!_KQJ@?s9L=;zKK76vy>LWaD+*Kw+JDRL0pNVeqlDyea z;oD3n)i-AduKglx<2t5F+x+m=1FIv2z={Vyw7ckOXaAU|H@v7`{nh*69Y&k z74}%iH+^FI5_qT6-`|pVO_~3d5I0*d?ZBB+Ia^UBNgnK}j|imY@J!RF-?e}zZm_oZ zcVlI1S}a`WZ_0SfPM0r^y)Q3u0;Z=6n$w$Fy*oo2Z0_l0y)lI1_g53p_N>E7C3y!r zY)DQ~!4lP>W0TCoycoK;FE0~jn zazP&?t3R6<94^i4&&sGAg53#MxI5QyC*7#lKw|%?dOvzX$fUVr>boKja}D+$a->N3 zp6U2!FfB*n8`(v2xmSu0u<3~FAi4O1kGuC+=DaO)?_LOYk9UJ+G^d|h(mR^iYbrSkpVbd`@?Z1P`9ejPLwng6wONqvh!;iHpy+7$M_3;B8qNT>=xzF>m zTqL|~FacGl#CaLjP#_qZ}1A}NO zsHF^(qhK7{**5TZo{gHrojZ<+gt(t;(g|Rds;I?<#rVfJT}jI)r%C(;^EWPMY4L^{cneAE44jSSW&8gzlZ@L7{nm%y zKyDMfP=+dJsDd~RFP$@xBkJF8{xg26;%py8eG-`cnuU%Rf`A zF{J#!5r97^^xrkrRGO*8Jc{c|zIYQEF~ITHoPRc;D4K{rs_5HTOsQp-YXdaC4JwXH ziMyEhKrkJdNX1kf8D*ZZ)jn$Q(#Cwbft32Rkg+D6su7lS5bA%8(O(g#`DWJ;rQ5T3 z+>_Gxypau%-zAud^?K{h7DXqlhI-gk&fZC%kbM(SWEs8InbO9?{fQ#`qm7~}&3lK% zgF8oxcBK*W-9C)`^x}_Rfg?>R+SgAZgJEi(=?xk~=J#usm93b-*I< zL73cN8Xg>PDh|FSc@T*vy}k3^zp=QQ%>#_z(q4er{-uKcDpF?uq#S;L*hpJnd}28u z9?O7^uylW5t6go0&k=YSvpGD1Ty zu*9S=Bn}Uu0**S8H`c)lK-j9615zO10Ly@f>i}HZc?48mdWFS?+i5KJiF{YuLU1;` zyBrY4p5`$??CJgKDDBj6T&d~he~VC%mUWPeQ;@6T;{ex71As`~y(@7SA_0-Jkdjus stDq<&CvoXWN#(aC%=|}ykDrSN{Mr8=fM0@mT?PR3w2U>Y)g7b%0UwyXTmS$7 literal 0 HcmV?d00001