From f1c7a3e06d5ee33e9212fbfc3c914554efbeebce Mon Sep 17 00:00:00 2001
From: morris <maoshengrong@espressif.com>
Date: Thu, 21 Jan 2021 15:15:44 +0800
Subject: [PATCH 1/2] doc: update rmt doc for esp32c3

---
 docs/en/api-reference/peripherals/rmt.rst | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/docs/en/api-reference/peripherals/rmt.rst b/docs/en/api-reference/peripherals/rmt.rst
index 4540bcf9c8..5c9684d2a3 100644
--- a/docs/en/api-reference/peripherals/rmt.rst
+++ b/docs/en/api-reference/peripherals/rmt.rst
@@ -99,6 +99,9 @@ There couple of typical steps to setup and operate the RMT and they are discusse
 
     The RMT has four channels numbered from zero to three. Each channel is able to independently transmit or receive data. They are referred to using indexes defined in structure :cpp:type:`rmt_channel_t`.
 
+.. only:: esp32c3
+
+    The RMT has four channels numbered from zero to three. The first half (i.e. Channel 0 ~ 1) channels can only be configured for transmitting, and the other half (i.e. Channel 2 ~ 3) channels can only be configured for receiving. They are referred to using indexes defined in structure :cpp:type:`rmt_channel_t`.
 
 Configure Driver
 ----------------
@@ -211,6 +214,10 @@ Receive Data
 
     Before starting the receiver we need some storage for incoming items. The RMT controller has 256 x 32-bits of internal RAM shared between all four channels.
 
+.. only:: esp32c3
+
+    Before starting the receiver we need some storage for incoming items. The RMT controller has 192 x 32-bits of internal RAM shared between all four channels.
+
 In typical scenarios it is not enough as an ultimate storage for all incoming (and outgoing) items. Therefore this API supports retrieval of incoming items on the fly to save them in a ring buffer of a size defined by the user. The size is provided when calling :cpp:func:`rmt_driver_install` discussed above. To get a handle to this buffer call :cpp:func:`rmt_get_ringbuf_handle`.
 
 With the above steps complete we can start the receiver by calling :cpp:func:`rmt_rx_start` and then move to checking what's inside the buffer. To do so, you can use common FreeRTOS functions that interact with the ring buffer. Please see an example how to do it in :example:`peripherals/rmt/ir_protocols`.
@@ -267,16 +274,15 @@ The RMT controller triggers interrupts on four specific events describes below.
 
 Setting or clearing an interrupt enable mask for specific channels and events may be also done by calling :cpp:func:`rmt_set_intr_enable_mask` or :cpp:func:`rmt_clr_intr_enable_mask`.
 
-.. only:: esp32
-
-    When servicing an interrupt within an ISR, the interrupt need to explicitly cleared. To do so, set specific bits described as ``RMT.int_clr.val.chN_event_name`` and defined as a ``volatile struct`` in :component_file:`soc/esp32/include/soc/rmt_struct.h`, where N is the RMT channel number [0, n] and the ``event_name`` is one of four events described above.
-
-.. only:: esp32s2
-
-    When servicing an interrupt within an ISR, the interrupt need to explicitly cleared. To do so, set specific bits described as ``RMT.int_clr.val.chN_event_name`` and defined as a ``volatile struct`` in :component_file:`soc/esp32s2/include/soc/rmt_struct.h`, where N is the RMT channel number [0, n] and the ``event_name`` is one of four events described above.
+When servicing an interrupt within an ISR, the interrupt need to explicitly cleared. To do so, set specific bits described as ``RMT.int_clr.val.chN_event_name`` and defined as a ``volatile struct`` in :component_file:`soc/{IDF_TARGET_PATH_NAME}/include/soc/rmt_struct.h`, where N is the RMT channel number [0, n] and the ``event_name`` is one of four events described above.
 
 If you do not need an ISR anymore, you can deregister it by calling a function :cpp:func:`rmt_isr_deregister`.
 
+.. warning::
+
+    It's not recommended for users to register an interrupt handler in their applications. RMT driver is highly dependent on interrupt, especially when doing transaction in a ping-pong way, so the driver itself has registered a default handler called ``rmt_driver_isr_default``.
+    Instead, if what you want is to get a notification when transaction is done, go ahead with :cpp:func:`rmt_register_tx_end_callback`.
+
 
 Uninstall Driver
 ----------------

From 5fe6c9f8ab2fdcc0a788adaa8cddac207a66fa8b Mon Sep 17 00:00:00 2001
From: morris <maoshengrong@espressif.com>
Date: Thu, 21 Jan 2021 16:05:34 +0800
Subject: [PATCH 2/2] doc: update sigma-delta doc for esp32c3

---
 docs/_static/typical_sallenkey_LP_filter.png  | Bin 0 -> 13786 bytes
 .../api-reference/peripherals/sigmadelta.rst  |  26 +++++++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 docs/_static/typical_sallenkey_LP_filter.png

diff --git a/docs/_static/typical_sallenkey_LP_filter.png b/docs/_static/typical_sallenkey_LP_filter.png
new file mode 100644
index 0000000000000000000000000000000000000000..b6685bba9dfc2d6191d43bf465a9f215693076e9
GIT binary patch
literal 13786
zcmdsec|4V0*Y`e$l7!MAA>%P5q*7)lA!CLzWelY<CS#_fq7-E&iAr-hq%sdjWe%Yn
zI)-B?iBP5x-gO<n`~E!l``pjxd7tOKpFiH$=kxn<?Q8FSt+n>rYxu5Jl=0z1>}$8J
zMF_F$>S&rGw5kXpro(ISF!FLJ*%yAXdg)l5Lx|%Y_8%@uih~y+L8PmB;AlYlXt%Ck
zmSq9Sq;~T_eN^AWn;q(Mb{B(fRwX_5tn88E<>3(8xG$MLiTh3-*#Uc@r|=Wzn1lUE
z)Of`Ozeq$W9Q<1I|K`KeJ3E}9x-ZS#?2~-si<+r0dDkzBH>6h~l$%n-MK_VE8~F7A
z*yGq`f#*9~@S~MjWBPfknwqWGgGfGWkUM>AHgiX|YnpVN<CFXEL;s8f?yX4%>31|J
zDo_sQ+k6>(%2?l~M;bW!NI#vM2_a`gDctprp!#V2VwhR<L60=Vr<_#Hs(=tB;T0D>
zvE|!k-Su!v{>NCoKGYYkJlG#&#iV{G3AwNjbt~Xl5RxF7<N5XnksIq-6~-cA=le!d
zxC}Z6Y($j7Si8fltqw=zm@0)k%o7tDT&CF6^VHi-62{)bhfcrj%krR23$Bcm!HDA9
zk987W&u6bY>BFh=9r3s24&o<`PIo#EJg~IbR`Vk0TOspKguH~PeycL}1+m8Glnr!%
z-l3qID|%p)!wgS?AN1h=2%r5geh4^hO?9`ev10=c<o_-ZP98D6=w$ewB#2o&dj5(H
z$W>JTZ;DCxTim4E=DR4cuq<~B-rU!f!i~Ld)f@!<6+Cc^b>h<T$Idf1VEr(h1#if0
zzLja(QaF$O%36-EfC-%hb9~ncA6=>>cOYm7*Zm|^&|yYoY{3u5l$9g?Sz#lbiB60;
z-e#PVex(K5eFMBoiP<Bftq%m>KSiKamD{!Y)@#|}5XlD~lMc^t6v6ga4ol(4{`6Pd
zT>62GD2e=}SMIcY_tDpaTKO>xd<qL+kF0g+?@+OHq&Y;nU);QpGr40QJm_e?V2GGb
zD&8~8q4H&r4oX5{dY=TlAm+ad=wJWfOZ9z0#RXg|&VKgv`!-o+(759N`LF&DGW6fs
z`fozWCqH|7rgRjf%(}+{6b!9DMS%aKaPxoV!+~yJ+fiS%yS;rn#Hc4A9QNMsLS|MN
zYd8KynS|SKaQfeV^-ok8o+u<!nt$bpCn(>Q|JvzbMxL_jd%kTLk-C>R)44$eH1-1A
zal1ZOgSmNNj!u9bzgTW#-2hje^aFbs;jK4a&v-O~TXjYQbaB_cBs4C6DV}`Vrgbwy
z-%b-Kv?rpVqvBvd>I;1C#pnSa2C(tk*}!{-UGiXd@*K#_5;gS^$0FbgIf!I4OQd6y
zMq#TjzuyZlMn@TAk6+Fch;`;o^{^uKK@vK#O-v8Fjt<<gAbFz~5XJP0>rOD^>ivMf
zoSWXk)R|U2(i=tWrgl`RUJNgIO!NC_c=EELwm{-BV9FiiqYc!V^aFgJV-8d7vwZU9
zWlwUDT+#4pSf3A`;9qjW*!dvtXSDpMPsyieWb#~}9FNP<&(3KMe+>r4131c=xvBEh
z{fpx(o#i;E7f$m>;gb0@RpPGZJyQ$5o-nl>5)#jJ%`Nb0Sp$$X+oDG*STNYk`?4xr
zOZyT?LMPcApEy7<uG?!iC2%w3Dbuy*Igc>Wv4RXVoc(`r-UZXs3Z|^{8O_gAqVw19
zJt=~7^INgucpxBRtF4>wfN+UgDE-OGj+sHLnK~PURh|8>f`ckeF5)5`I$`1mf@}PH
z01!~yW6cKYXabkO=-a_4%oq>1=^^1*FoJ?spc!`hmHoupj`CVBcMHt=VI+9I`f_qF
zi-+aQvl|NDfUYHiGH)pK0u{mxx!sv3=D-90qC#$MIOq}TpWhg?3N@uQvbS-{ypFcc
zIh^;iGd&4D3pSiCo8?50Ih0#dz4i*(HLdgei(lC)D+}#h7skHL+g-9fqL4LKEHk4-
z<TCGZYwtZBxyt@`<j3~uiRDILS+V`9(v(THUYnD>VjNvsY!aV(x=pf~$DGK_PtV--
zUnk&ml^F%u`nrqI2`AgWCwH6V?C@gAX5PXAF8_QR>n3E7E&96!ccVq?j#7d0+O7jq
z;mdqF(>(<!^_b#U#hGfMM2dbYUpV-H((b;fQ+Jt3o23f2_tq*ZQ`Ror^ODMD_Pdo~
z_`Pf`smCn*pad>|Vh3)2i(bI%Juz>UH=_M<^ggquKef#=uKPDPEr`#oB?bre9xi_P
zlY^P^kq~oGBHX{&YqqsvO*)u}LTzj63k#eeYl^_cnkmZF7X5dl(gmb4%p{23&$RoK
zetb&G(V=ed6&+D8R&XeSCf5T=1Syw@k~x(AC<)cb+onuUGTm>M<3uXW(|VM-^hcxh
zJd5&%o7N-JhM@bgo6ZqR)AoxZ8JE?}9aY;UMRmaY7Dh5{M-ms!-_R5}`QS<!kuC7c
zR!WCnHA{q=>7*s^?rq&tBFFZb-j_>0{XO5e8%HPEmSjmSJodBiQ^{stqUB_ZjT=Q8
z)>3n)KO0@Jd|0#NrF!a!dUj}XA3@Fk(6bu?b2%khZKaN!TVzc9J#=tpX4&OAd_gRE
z_R3$>6jH3`t6IVbq%J#qWyg3*^&BBp&UCjp-C)UY!<3{Tz06bJJ|#pkd(eC2V19|V
zSL4VVezo4+?P297du{&cykT?i<hMOPk*r0M#-gKRbzjJ52$)@4*Tup@|AF1I-=Msu
zX;Ks%qFgb@8$XoZFgPi<XnT0vMg*bSi!gNO?f%zsp!;;A(anhd`~l^sd?H_oz&?Z$
z8*NyL;l&RXy|UXwH&ihrQVKYb*fODOg<0$fVP|(|@9KlFbX_)cKvT2l^dxT(;p)C^
zyTB50K#X;@pBV(J00E6e0v2#6RKK<j%(+FrP!vk~?!TmR$2Bcf`8myRhD_0?-PM1K
zrzG4Pz25Va=dQ|Ey#UDy??-MU3&fYS3W2qS=GN53Fq17TtwXoDO;3`UJ?^$ATxmH~
zH&k0UI^bUH71dnb((c>lYb3*A9B6d;-20>n?Hy{Kxvwt2${TWiv{pure|4w)c5m;q
zf^2?=gwDbT_{R+roy$D<Y6-+jo5yTuU#ngKTNE>C|D@U)$%%wD5c>vXE&1E<_C7lq
z#x~?9geK~Ogu7f$H@9t<>^daXCtZ3CO&kkNVvkB)oaT)c1gC){ZeEmw_}YfG%dyz$
zOztX@xUT4gx8I>YkP*7$MU(v~Z?ohu<#5>&m0mT+7vvhT5^Y?1q8^$(@UZrDkL6Z>
z=@ki{nbI+2lH3-E0&Y24>(cVg%;X(+Y|LjjUx~7G<7n02s4a_<iX&MBa`diewT&0`
zUvY`Dm3oN22?6hd&;`dKJs$-u5Ia7JMP-Eim<-8yD~QdeXw^4{xx}!kHlQqsXgmt!
z))2<7oGQFMG{bUZr}V<~P5+QHh<+@~b#<pmg!O4cX;mw&?%Tk~<+#|mB=;ra_yj1>
zP-A&!XgB|loSf2E3Ydv0|JF+`-4l0#iPm>2Y@{PuW#@^<%;?@$@4EU!BsOf9I;YYf
z*OXHS#Y$!_CpV>ZdJi-|Xm+KoCM7hL-fSw*wqLR$Ww@5$odw%vuVWf)R|{I$%5gMa
z`kEV$^aedaS8>^otB~izB;@R%klLAX*!-(^g<2FiVahEq%eq13=4%MXkxuGwSY*QJ
zukoZ`g?6kcT<SX$f{X<C#p0ho4?y?s^+W^z<8VdRN0XHWQxKZafJkc(M^_+t;Ce`A
z5>G!ln_e-p3%d-e7jb%R@{Lr%yk{3bx<9+MUcbAYC3$|aC|FC_bwtGe@?>bJz@m?B
zo9g@=atJTtLR&CTPU7Be0k<slm9r9OtN0DugTmGikJ3F#YS`~_XmralwfdZ0Ewg<=
zV>_=Po^%UxA&E|xuL|iZT^d^v$wCe;+^bFvxq13%dhIUGyf2kBi|Pott`ZsG-5h-l
zCvWc44(nPt%ALIla)%}x);}%^Wq&#p`^32~6NW^ps$G81?*cdG;Tsy(x?R$y%7*pm
zr(SBGvX^0b!Zju|;XO1f{v+;9#4E1UK-tdeF}NWh^szrn_f<^`!AJikF!=R<9WYjA
z>SsL29?{Pb4>6=x*{!;>{zQfM`Pa<Ijy!t1jO{^D?<q2~;D!EP<!j3<cx0UG`c?1z
z>GnHpuYJ4QeSa<+01+~Mzt7s{9qRn5=Qr743Im0D7Y=n=G$n1y87^k7h#-z}jeffv
z7{`npN}O-xH74=JeVqk0Lf(m=O=f<aBP^;br1YkR+R~h}xM7&bO7T_c_ccoMKYu50
z)|r%`+0=O~7ARJZW6`RWm*$*gWtJNiOV&t3>r5Q{=)#@WZ%eNh#fxx7+rboPP4+q1
zIUn+IKVR$Sr5CQHs>Tmn_NnJKdJg#x5Q4L;`Xe@7X|Sm~@I*^ir@ghjY2N-ox!dH>
zmnHf1r3^2sCx?+tMqF1#OIJ<)fzJFcll$ktRGu_lo=81M2+ElcqVK4DY27z<G0SD?
z&j7V-qj-Gf)g0x$zSaw?HV|GkW?EEJCnn>USY|dJmdS|NUEb1FnU9l7R%)0(F!qh)
z|HU$3My`NNX?2NOnz5+0(M|ldY4H|I6z%sdfeOKUTl428_2#$jv!yO`pZNJMX)5OH
zv3zzN&F6jBeR_WP+vhmv>ts9Me{jLKPKmE%!Dnp?8*qI-bLeHTs?BZH%>#9tQ?G_5
z+P<;TeV33Xib-0JYqnS@itj{Crc|A6o3F3+aw=2ln{lI2`NG4A7Ri~tL+V5F-kJBM
zPq&qQAZK0(F6eRc?)};)7iwwg-J5UHN<07Dsk@*oTXsJC>C-cgIa=4}NBpYzr6rG(
zAs$2Y9bfgD&Wz0OzbSWjRO>3)f77hQEzL76=NDvy^D5F7mt;ePXEjPbmEXGGQ?Q-$
ze9OKt-h<51zmEsr61CHDDi!a3<+Of8@IiFJ^yJb){=E07|L+~*a814Id9OpXi0C{(
zy(@ux*HO@Zil3C0V4UT8i>WNP?7_lKUoQxr;JxhBXmMm6?N1;fgni*!D}PU~YEeMH
z-n{lXY1(Sf+@I@z-9D5y%y%N?gI??08N7(S|B2BN<E^mZL@>KLZ%ug5S?`}a6Mx2h
z<;Z965$UuDxZGie%XSW#{2XNe?Z=IRX^OU#^4=L=iFo&=(yofgHvTBvpts`O%{pVf
zr^cLUcLLsq54O54wZ?rN-7r#5d)Fh<pTk-1yDDC(zG+-d;idhT9Q(#HWuCVKE}2Ci
zZMPKG<yyDdclFqDRK0A>9C8h~T<i|XaoRP{x)16<;-`&<cpJHBtE*g#$?9YkKcB$g
zYYNhoYj3O3LN0gc8)bYp@tZkE_*5|7-y`wK=k{a`BE5Oe&5knm2aV26lYHh$WjA{B
z9AB6V-p(4O4e6OLJsEM*V#%1esTH5bhDSP;Uj}v{*|Vb`ye+bS&yyxEzZbU<tjrqa
z`U)AE<#BKmel2=4y1V>w==pj*q+^wKsB_MiCV%gv%s!^XN>?^70f<8r2_@pslSY$|
zjp0%1{BzO8D$RVKgg!gPES3^JRy3<SA+b<z{>xzf)myi@{%pacor>)W4BuMBOeZ-H
ziK!{pXMjOof1u6Rs`Tvk<gY>7OY7@i{VXcnh&fx=V^JZFq_R?PeBCzR<fX*)>6ZA@
zMsk<&rRlfJo)>X)fO-(=d=S<&?bgB*b+I7z{{YLNXH)|E`IP3@P}4oajUN8B3}bz*
zkDG(@=_g4pdv4;1f&bfn#7{om)Eiv|fSJkquNZKBsqm-s3uS|ph5EWG9119!Tu7MF
z>C+(pSi7t^cfFsT6_NHdjT?OyiFgLy1gQH9{iG-=Ag`3(ObjKBD&4l~G3`8cV0odQ
z`+oLp$SU%$N!~AQc&n$3l+P-NwlJT%gu6KHqFl7;IRh`d;`UKlO}(%z+s$Ted8-~k
zM81u8M>c79tCl;h7Hyy2#_xiHKDn1{k~~>bJ(Uw#b(vE}b?C(d2Q~}@BE2krX!S%W
zlan{Z+49Vk#iBq;#$<<SZXD)eh<y5WPPu9(d9IQjO^ooR@O{0!W-^~X?}asxIsy}g
z6l%a-k66ZDe*t)ft>2<~EshbC8R!VrQn3M0N@vY~!?Vo3bpHWnK5y{wfC}F1Jm;QH
zI%v0&3o_zegzgZV%7yH)gFuY^#Obm840;vjqw{u$n-=_-@&w40rpUsAW=@aHm)GpK
zEjZ_k?l2$xyfxA|{~dsll@`7(nd<`dy4%gnd}C7hcjxa<<P%I8^zakuTyj?}QrJ}8
zbg+Hi?Zr>#^rY$+zt+_xU&vvc^!m=x)AIH~H7_2}A*li>jqsn^QnUNA!kaHZrNXy2
zZNl3XUPBNO0}(xt`0tQQdJLc-Ma{wx`xNC%A?MQ%d<yx&Xz>6?clO$|Xd5IV^c+J4
zcy3*fo#MamLCa|)R2w055>O4&JqbaC#35=jPE$)!Xj#obj8V@6Pl;-yv9`bIo>vAO
zQenhImD)&kc<WgR5a^;<tXtSqS1lBWh?<O#Nx5`lxG#f|tNll}AyPv6MJAP@*+-yo
zzZTpIn@oA+6!Aov&&A~QARR{#0P%FPMpWEJM3TlHsv~#ijcADKx4ipgfC4PlkG3w~
zXyIzbjK1Cn7LEiF<m|kL@G|TYh87V`fbnhXta!G{nc&ebjKhenw{I{ZNnYF5*UJJ~
z1W^rO(0l7ToFJQ&p{9(`Do~S6RS-MXR(*3MlYi(bVQ6suEAKw8?UOv&e%%jhXE`J~
zsC64=-w7$51DR~Q+$jkN%--%ji)$#i8r#=LUDAXrMcSFo5?5BFX;;+#K~t?FcaeoU
z6tXS}Rl%2ipAHx2lVg(C13-^RQjL-E!vZ+FQ&eAT+rcCT%4Or3A6-j8pCUK9&$q<8
zn6JhT0u{c$nQ$td#FY4hxMXZ_MGJ;>5*sS<UpfOeb8$-v$$)myx49HYis2J~j1X)e
z&9m@I3$4XQ^;{0$JB#NqzMoKbP^K>s>_EErNZ_NBvN&}0tOK=4%PtCnKCiBBPuret
z;VE8b7Iz$2n#$(}4fyW;1%waLLASh8CSA;wWp51u3MMZT%(=&j)j8XPX6w?n&Yxmc
zy!rYbA4ES62oGe=={R%(6L}|1*?&T@BDehG{GMC>h41RQKUi!<_pn!i)=FochAXpb
zjMTkrhC*(XyZ-J+#CFC(&qT&Ag{ci~IvmL*!l{2U=a}PRW(Kf^ynT0`d%yj0rl-uh
zNZAITOXAhv5h}q{b*HT_y<0xU*t@9jnbP9t`C=S#9&j^esYB=OIraJKVzW$g1Kb=A
zNOXG4XaCe<BH5fG5c|x@9JxLL!x!*_j#TsFyyLS6*T1AvQ`O$~G%t9ISD2T7MC&5}
zh;kxadCtcyV;lT)<gAG1)SqfexHsc{pUK3&WSP8xAHv4_0Cx)54Cq~Ny=L9a@r@8B
z5dMxTq4KSfx#_8^Q7Ht;yWZl24C)Aoq7M|zar82EnCUwt+u$h?p`p(*dpo3XVdt71
z?(kXgS15Aa*RgH;=&l^JXY_~ai?H~5!`E;tfnU4h3kPloWxY{S--d`kL26%qt6Wm{
z>xnUb!^Xe${xKdC98_3}05~k+z(;V|InE3@j-MP?%0a|Rn0?}NklCucmrCDjUu|J|
z#5+0ETovKk|7bOmh=w(mWE1=m+qUTZ$>Br!>YucvR-xD}=YZJuuyN_c*sO$GBQsT0
zfnjWZJob&Z;a#mfEPsPcBlf_RL!<qCd~|7Tm;T_xY0qtjOtk?QD}a0@(P$jBDIcJM
zM7k^c&9cDn?#}@Ea(=&(Y(iEAKmUmSgU%wB*S`Ego52d(y*Nj}$_u<f(mHYfrkdao
z(FjQ_J7lz6CT<KPuW*L}lA)q`72MsTv8us`k0PFRo&O%=zMXz##TZko<L6`&1R;PY
zh2#%Kmp`o)Kq&Am2g8s511WR>Yyswhh|@K#?AqwDr%Qz?w0YB!k#i32z!{{#l%P)u
zLDaAqu{N!z8_S$#I>BBSf(lC1e199Om@gaZ5EsYvb|*Sr>`WS)IC{sz1j!7+u8Mvq
zt{vxGI42(Tdtm-g?Tl7A`KfL2N-<`WaMq;NB`#7NQ%>JoVV<%jrdYNiI_hk2m9>(<
zZLJ$Q!AIH;*J;x|b?%c+Bun+GMT(+4FE`-W80N|4OlGdN+tPh}K{XO**Ka`Jk+v?#
zPBBL^;PO=JdsHZo_7rSZ-nDuSvc^z<%{%-|u{%K;0atp%@ZyZTYV`FL&oB972*cLs
zteF*RuMaM7SFiZg>^YirXVXD~iNX1|BTwfxAsN8hREFN4o<o_NHlo5C=J-;oX|BTh
z-TAWpvze5LdB<N*Pv!kOFLjW~Ycu$Vp2x0fIVB%i?p2euy85^ZjWhMr$k)n*XXk^5
z&9z|z$Y38qid<MnJ86LEVt~Dx>ia(!R^P4s^Q=SMbTfySLEB=^vgeFvudzY#L!L!y
zn9ar2bS{|a$0AlN%Y*l4J5De4-;$7&&W=*N%D4oBUKSmnuN?N6^7<6ta?!%CkaOp+
zB(@YJK3#M_d-?X#r#)1;VS8Q|`$i6f9vso<s~*W>A-yYO>1>1Wrzj`H!byoRO_eM1
zH6NpV6ToVW5A0?63!8^BW+N(Il@6co3-q<NfO_mcCz**^*MZ=Ta{&|YqwAJsgQ%;E
zxFk=uO(Z}5Swv6Xu-R$nm!BH*tIHci0l@%Qckg}bPFrowA|$8`NFy?SIF#e$J;Gm^
zuVR;iqcg%_z2rB(21rmA3rEIYmmTWzmy7#0TaP0}W070{+a58L8-Y2NpzIrN>mvGJ
z)Nx=#ko6;CaPtr=_V5mDJ$uk6#G;uwu*(ULj$oVh>xgTo%Hc>*`9MTw*41kO%{vd(
zzpm~IHp4#uY~-&~q%0vuc^ew`v^SGsp~|4tYpW=7`}8@I&;7a2-;~5q=}m|OCSEmv
z`0(g*K6&GF&a13wd=P?RQfg~6JJdSp?qCr~wevRd0Y1jy!#Tk}k+MNqdaydYgFqEC
zDG!1T#CJCp8SlVe4#3O$EHDXP$&L_CV`X6^Vc6aNGVIJ<StW!vldxWZ(X@}A><xyI
zrn`cI=+hOd4?UJG%*?2Nf<A5Z_&5}wpD|ausJ>^BSCokeg#pTI?YquX7T$FYWzMA<
zayYC~jciU564!CY>f4>tVS1T;|D)HPR1_-<B#;5`T*sN9Z#NR*ON7aXFk?h1vzgmW
zD#fmh$^jVU2Dg_nIcaTX_UWA+`xTFYP9^8QS@D@|gVk1wjKVgmwGO*Xj}Zu4(th(2
zm@)-?iqd97do5wa-mp3F>Q!Jb4U<l(;UTU0sCZ3nopMuyI{~4|b=LvzLhCc7D)6x!
z5O#RQkcabaUVUO!$bA#dy2(M(<FNXec$zcj1RH{X2x_pp9j|646@rzgB$+?dzr@v1
z70v2=X8z@{OY$g??DgVq)KrV6aQGgeBV!0lR!oPU^Pvnd77!E`bx8-v?h%VkyL)tg
zIBORcJS&<Q2p+h{8i7UHwKp8`lHbBUs5M{QXbA8)9udh`cZ$uC6?3MGia4_0MO>;)
z!$y1bc8GDv)^$$|oOBX%#kL_xJV_<uG&kk}@5uQ2^J`HD^{yuV;^f~s2Q>hQN~_Yw
z!b0}mJTs!yC>r<m7_Kw{lo{10Rz*i?;$sDYd6c*_izngXh-vM9goRoqf0mA#nVA_5
zenL+#xfs0LKw`$iCA#$PG&mMvOojYS43H(5CN!Z9`Uof}LOuF&I0rp!-VYFg8m4m2
zcR*(fCKU&Ez$De#b>P|Bs`Ea`_w6fQ6wVaroQ^Wz(v_h&6FSpC2=YIUwlkFS-QF;_
zC^3r=a*3oE19AjJaMRA~jnSj?no?Q=BSYPJ=bLY&ONcR0M3hT&`}}RW!`@PK{>ff$
zQ-chPg6UC#lIoOg0T(clIX7oIo}(C6IS<Fb$huLnqb6FT?pw|v7acctkqHsGlC@37
zl!LyZ+4>@yo<!$wM4E(CM!C)BOTVRs`QMH_=kQqcylRnG^`IG(h`sx$;6r^979AnM
za?NUOKRGA-%C+**5)hixlfy~eI0s<x6|u!lc`ekJ-Wfk97djr{C2nG3M<j|3>qPqB
z6G9}~KVq!AWtMBK@o?f)M(KIivGEsUXD1Jny$mj3QZ?PrYZ%E{tr{U7rw73dHgw&x
zSZbpBcx?1Z?c~Rz=mDgKsN<3A(&90teNE?|tGf+*X4!8rClu*YeXI|^9o}Z|Ot-^S
z#i+smu_mF2Mzs-6M4Vm%prd{xE=mvUoT%>(*%hqy7zs<!fVK#Yx(M?#SBy=c7Q2t+
z$CPbZj~POGVe_-(L1pQ@rk!<@kz%dQsXC$*Xc<9hDKAk)+ez@PnZEXoWhH5@#WNyU
zK^KE~DZC-qmHZ7~E>`k#_Yoj$agI~pXR3>O3_#8NZ${o&5_vi2G(7q<NlT|aIri*M
zzfs%o!KOv>^}rb1stMtP3%}p<EwYT{^S{2)$&w?Bw>qMW)r`@^7X2Stu4zdnobTIX
zr?o6w+6QjkRa#>d4q_4q6}3BlLdTiPqUd%^S51A4q_QQ6d3%2RXP4#rTN|)C<b?2y
zf)kHM-PA<MG8A<AZ>k#*a1K$Jv5oB%nRqyotbMo;0PYRhHhMN6#G#`DB{r*_@)<cq
z50Q~O_6sF3Gb%t=_Eg|i^Pk&Vq9$Wq)B#-^$nV@nzTNlYp<xJ`aefB+EruwkaR#rY
zlcue|6P1o~q3ckXy%=fZ-Nrhj!Fpd;qUa)Rwf$iN4y)-XjFrRj5YsNjD;Kghy@uIM
z&y>e`D2gfm>~}8>oj9LcJmNC=C)*1qxP?_Mbm`q13)@dVl7BQ__>;RWSm@sz_#1$>
zr2GExi86jOxtpEv$=!uw_(XL7&#V5Mfo#`BsFaep)&<=YzoE##Z=y8#pze71G`F5d
z|K@Qn_r-BjiPObR)GZ_@sBmo?Iv4eJb)lKPQu5feb-|BOdsYIrQ3l941aeKAukY&=
zIC$xDZEPvenG=`7F2%D27AZIL?2qO5lyI(jZ5w`#UtyisAkoGuGx8k$(a9&#(KGfb
z+w;pejWm^Z73I4=h%b$IElEB;pW)q0tC@fOe!tytF!il@K+1cp<;pSW5!l;%y!$?n
z@+~~MnGx+|G{$2$2I3ZUZ7bNGASQ~n$`q)kD0mBQknO@(jNSSiSeBep^7bf~MD;{d
ze8ApL1uI1zm&T%4XxVYpmpMC#O5Y99Tj$p&P~RHuU`^bSa_SA#F(|g}=b)2-!j;5q
zC;a+Up8vf|7hp6d*&9YnuTqPD9OVjllyvHsft-o%Ryf2UL&p3>J-p`rTW$fMcZJ<9
zGIM_%O6Bo_LOWP@(Zn)TSZcIPvB~1mV|8bGxjP<v9I3cHi9xfqH}&wc+^TUDE~w?z
z#_EqQ;ccFIEEg<R+P+K`&$u5?xwSc2=izdC@UrwetlH=o7VcCm)@O0!(adG4=f3m}
zK<KkvO^r^thon-%?j669^zb=mGlN>X%Uf1scYfAXmz43GD1%+pG0@2*O^rzGZ}Ow~
z6<2KcNZs?#uijsccCW@0dZo%Q>EVfEj2U<1QPg9a`JExGisoI$JM!XUb55Ipc<25Q
z@g!y)P3qo7<?g*HU5gw#y0D-}rp?&Y%*>j4T_Xx~*>v)z{>f#(`O3~i*VPKA8c0dZ
z1G6l1V5|aOgT8rM$oyQ`OMVcK>b^t4qyu*ZyI@9yzGFLBV<Uc?9kkTmV80gg=ho{=
ze0baHyh_rWYiP2;ilD&zA%zZj{ct2tjooFSW%wpVZmrb*ZqL*yFgvA}&G8i4ms|SV
zm5GZxMGg-I3c-p3@UnFBK$%+QVCXKzZ9>CFbvJvioZS^88EO0rh?qExHP(@DJ<jHn
zlvZ_EQ0+m5&|-oWw<sP`vzZkoCkl=6_nVDQjUDAe&=VFCX}nvB?^wm9%KE~k;?8F8
z-<`-3Bt{&ENDd7;OD0YUSdDY1*l>D}^Bdth?qx6At|b^!SqZ2V`oY{@bLnM>rXU*~
z0*)jJ4TD1l5=Bov0L!7PBr&68sGdzoq-?`oY4X)Y4!4WA91;@t-<dlvpTJ~fsmRXa
zApTMmSv{t;U-z(qaQYFCbofwq*Y_Yg%S*SDx}-e!ootz&el?-ozvrTole;q%OXtL(
zX(FRdK8DCKu`7w0&egWqaVvDysmqFh(RkHQJqTW8&uS)U>(h_dg!U&Ve_lB2XrfD+
zO)Y1+tr8JD)A_VcmB+>3wIZ}tdgQCEybL5X{T~`|V*|yah&wGZ{tTBPmgmwFhZQre
zxBR@0_u2?F?!S3kKrz?a)kuNu7;A1F|4>tUU}mA;W3D@B2P;v#J%`OzcE1v2UmF6Z
zSqfwKcp%4Nf7gQLwG$nDS4|R!z|Z!3iE&T@PwFD?LGH`YHbTm7EsBU~(WHMd=hB6<
zb8fKnP<qAXP%wP$_Y2lIrYwTC2{H!<BAKAE8#;uPgEL|kZ%NOTPlYuSQi8XT`aw;+
zgh1%-GhF7)Q*24h4w?kq+KI^UYdOo>OdoYI^SrP8W=Kd!D^q>wOJ)UKVVuM#x4k@S
zr^M%Y#(37D*l?lih3vbCe($55Yp_gUyC@gw<ET>5sm0^^VGEHP6R|82{Qa2YW6?v{
zMMS}JhTBVouT;h|B3zVvs+KSF?7J%ShOg%#R6?a6Tit3OlY9)@)V-&E=iGhwNqhGR
z#unw@(oSwOcFbPq&uAqho-U7!c6#76ZaNfnRd^$onm}0bANSl+7})NWx@<e0n17gi
z)%`z9`TH1@bv<5Mz8FR&2yw4;x1su@1-@oxwgcHS3ibyB6lL)z9*bY(y2l#DppOzW
zzx$V!fk9fV0@w{iqOn_P?iC7Q$e?+Hp-v{aSjdO&vDRUM3%YWekR~Cf`4j7efFGSJ
z3>qENdX5(EHqkiBShhh&bftHbuE@oTH4Xt{aa&VE8#7bLV{f)77i$z_G~j}!2E)`L
z57D^T+yAUDSuic1Oe?-#wq*jk!eIHoLw8~9zulxtI`mg|Ptsx#j`ilk&p!e$e^FKB
z9c6xXMM(rP><&>57*g4@z(%;+)bCyUmoU#B6gDABV9g1LBI&)7Eg%Kg1y+SvHHLWE
zri$L3VqNtYs5lEqAz+rg&F{{>;aJ(?pS2#UJk543Xb?K_9}~IqW&%qgh%X>Pg&(nB
zXExpO=$66>ns~SzjKhLtU=1=|C`uS|1B_(Z=3_f8XWP2`Q>slu6ibj1dbBP|llksC
z#&$05=@Q{PvHT9%IQXb>4F1)RYeR#hC%L+*Y^-5b{%hSomE3<u?qAaWOHECw?bB~F
zU;JFnPEr2Ih>QXTM1-)+92zy$Usxct`-4ySu4CT4?`oJb@rZ<#2Pk3(D+-5$`2cvt
zT6K||ue}W5KB)CByyNg6<icJ^!i&*!?u-|vkh4%cEWR*aK<hB#JFAwm26#LT>P^41
zr$|!*U}dbPU&G&kH3|{yL2VUIcrsRVK@LT+qG3@4VjQSUE`hPy3J#RMZG^G97Qj-J
zVpY#rjVXO$>t4pBK+LN-X0A-S4wI<7NgFT%MSzYj$8RFo=j>MU`()_Vh!w%Iy?;Sd
z!9VLtV016WLWNU(xkJ8jUL<9E?yrI@qZdn7a9gps+TLKJ_O$dBn}sKvq56OoKyp91
zyi8@6$o!tK3I)T=FB3;_$cr=rB1t=*=X6x+p@7w~ndrVF>0vvNPTRQA^uop<0^Jjs
z6K&LFMU3>r(r3wADCPadDJci&%BJ(cOE52>36#=jUlnB1S+LIS2?Tegolgzt(okhD
zU<r*>(DaGu+A{JW6h`R@3I4{~2L<<J3B~2O)c6=4DRA%3Z_2`<S}cp?JS)b5h+81u
zMXnFSvno!FkcHwVHxiWC5Cx)Sl$t`9+`~%dLc~CL3b^ndhZtqEEd=kH-q2Maw;+-W
zmUP&LiQH;AG^17*-XXVGicnW0SZ4>ru$tbb<z|;_%`VovgXB9CGP$AK6gK+pIAf6R
zG9RIbCu)B#4h`shIKmO8ZE514FAZECR&LXSRDvN~M3IMt!oDhieuRWU8-QrsweQ;N
zB%C;bg>Q(|(3JvFG$X@CUJsNZqJ0DZvH*6G@xv53AQiYolxZ@iWz8!lwrUPC5e%t^
z7q(5H`j;#jD?EI5g8FH$6!>zWC?mlrm4K;tZ-&(^Sn7{dj_bp=It)#r9K_;k4PnOW
zjF*W(2zH+UJ$QT?o21v>xgP9RK-bh>zPpTa57^}kCOq&8qB*Qoc~AiUzKZ45V4eS~
zO1w<%;UAS)bJ1ige|(@THN@lOfqr>mh5VSKDlS8{L~h%VxofcR`W4k-*eApw4_(5(
z{*Nzy22EjO3Q<oIX*VXn<b{1{U!~mJqw2UUX?zHhKXm7l((ykkY{DS|*{L5^Dy{nq
z8vBnEi{z6`sS52zPs%qx546YB)R3IO@Bi9yF(rH1{cMQlLbk(-R5}e3KS1sXjF-(&
zBYbYMSZ#55b!o-1kr<Z#@kiI|SpzEYPYOOWq`miv8fh{!rK0>ej~9aqx{jUvn^O#d
zlYXn72f9#tV|Q$ATbtbEm)%LblluACMHpLcjYv?4rtkn5fYP2b)%<F0Pl?q0EUxFX
z<va#Wp~rjaaW`=(?`jxNTQ9t?6l84so&DFfiU$10EyXL_XxWY`lz#Nu9f}oANn%v{
zKR*Hr7G1a7IXu2(cUalNR8O*A_(lisXs&99qi1eakHh63mC2qo-f`WnLu&}V`THXo
z@eav6=i$}G5&v@4LmQ8KwW%~8%E732*z`yhZXaM=2QVq4H7nkGg+m4f2x^c2U%cq&
YJoK<&xrycVcVGwUY8}=jYdBo^Un!HPB>(^b

literal 0
HcmV?d00001

diff --git a/docs/en/api-reference/peripherals/sigmadelta.rst b/docs/en/api-reference/peripherals/sigmadelta.rst
index 0352cc81bf..17d635d098 100644
--- a/docs/en/api-reference/peripherals/sigmadelta.rst
+++ b/docs/en/api-reference/peripherals/sigmadelta.rst
@@ -9,7 +9,13 @@ Introduction
 Functionality Overview
 ----------------------
 
-There are eight independent sigma-delta modulation channels identified with :cpp:type:`sigmadelta_channel_t`. Each channel is capable to output the binary, hardware generated signal with the sigma-delta modulation.
+.. only:: esp32 or esp32s2
+
+    There are eight independent sigma-delta modulation channels identified with :cpp:type:`sigmadelta_channel_t`. Each channel is capable to output the binary, hardware generated signal with the sigma-delta modulation.
+
+.. only:: esp32c3
+
+    There are four independent sigma-delta modulation channels identified with :cpp:type:`sigmadelta_channel_t`. Each channel is capable to output the binary, hardware generated signal with the sigma-delta modulation.
 
 Selected channel should be set up by providing configuration parameters in :cpp:type:`sigmadelta_config_t` and then applying this configuration with :cpp:func:`sigmadelta_config`.
 
@@ -21,6 +27,22 @@ Another option is to call individual functions, that will configure all required
 
 The range of the 'duty' input parameter of :cpp:func:`sigmadelta_set_duty` is from -128 to 127 (eight bit signed integer). If zero value is set, then the output signal's duty will be about 50%, see description of :cpp:func:`sigmadelta_set_duty`.
 
+
+Convert to analog signal (Optional)
+-----------------------------------
+
+Typically, if the sigma-delta signal is connected to an LED, you don't have to add any filter between them (because our eyes are a low pass filter naturally). However, if you want to check the real voltage or watch the analog waveform, you need to design an analog low pass filter. Also, it is recommended to use an active filter instead of a passive filter to gain better isolation and not lose too much voltage.
+
+For example, you can take the following `Sallen-Key topology Low Pass Filter`_ as a reference.
+
+.. figure:: ../../../_static/typical_sallenkey_LP_filter.png
+    :align: center
+    :alt: Sallen-Key Low Pass Filter
+    :figclass: align-center
+
+    Sallen-Key Low Pass Filter
+
+
 Application Example
 -------------------
 
@@ -31,3 +53,5 @@ API Reference
 
 .. include-build-file:: inc/sigmadelta.inc
 .. include-build-file:: inc/sigmadelta_types.inc
+
+.. _Sallen-Key topology Low Pass Filter: https://en.wikipedia.org/wiki/Sallen%E2%80%93Key_topology