add automatic external link icon using CSS

Signed-off-by: Michel-FK <michel.stempin@funkey-project.com>

docs/assets/css/custom.css

@@ -90,6 +90,7 @@ body {
     }
 }
 
+/* Font for FunKey S keys */
 @font-face {
   font-family: 'FunKey-S-Keys';
   src:  url('/assets/fonts/FunKey-S-Keys.eot?b52ver');
@@ -102,6 +103,7 @@ body {
   font-display: block;
 }
 
+/* Class for FunKey S keys */
 [class^="funkey-"], [class*=" funkey-"] {
   /* use !important to prevent issues with browser extensions that change fonts */
   font-family: 'FunKey-S-Keys' !important;
@@ -113,54 +115,104 @@ body {
   font-size: 1rem;
   line-height: 1;
 
-  /* Better Font Rendering =========== */
+  /* Better Font Rendering */
   -webkit-font-smoothing: antialiased;
   -moz-osx-font-smoothing: grayscale;
 }
 
+/* FunKey S "A" key */
 .funkey-A:before {
   content: "\e900";
 }
 
+/* FunKey S "B" key */
 .funkey-B:before {
   content: "\e902";
 }
+
+/* FunKey S "X" key */
 .funkey-X:before {
   content: "\e904";
 }
+
+/* FunKey S "Y" key */
 .funkey-Y:before {
   content: "\e906";
 }
+
+/* FunKey S "UP" key */
 .funkey-up:before {
   content: "\e908";
 }
+
+/* FunKey S "DOWN" key */
 .funkey-down:before {
   content: "\e909";
 }
+
+/* FunKey S "LEFT" key */
 .funkey-left:before {
   content: "\e90a";
 }
+
+/* FunKey S "RIGHT" key */
 .funkey-right:before {
   content: "\e90b";
 }
+
+/* FunKey S "L" key */
 .funkey-L:before {
   content: "\e90c";
 }
+
+/* FunKey S "R" key */
 .funkey-R:before {
   content: "\e90d";
 }
+
+/* FunKey S "START" key */
 .funkey-start:before {
   content: "\e90e";
 }
+
+/* FunKey S "Fn" key */
 .funkey-fn:before {
   content: "\e90f";
 }
+
+/* FunKey S "MENU" key */
 .funkey-menu:before {
   content: "\e912";
 }
 
-.md-typeset span.twemoji {
+/* External link icon */
-    display: inline-block;
+:root {
-    height: 0.5em;
+    /*
-    vertical-align: super;
+      line left
+      line right
+      line bottom
+      line top
+      arrow left
+      arrow right
+      arrow diagonal
+   */
+    --icon-external-link: url('data:image/svg+xml,\
+<svg xmlns="http://www.w3.org/2000/svg"  viewBox="0 0 20 20"> \
+    <g style="stroke:rgb(35,82,124);stroke-width:1"> \
+        <line x1="5" y1="5" x2="5" y2="14" /> \
+        <line x1="14" y1="9" x2="14" y2="14" /> \
+        <line x1="5" y1="14" x2="14" y2="14" /> \
+        <line x1="5" y1="5" x2="9" y2="5"  /> \
+        <line x1="10" y1="2" x2="17" y2="2"  /> \
+        <line x1="17" y1="2" x2="17" y2="9" /> \
+        <line x1="10" y1="9" x2="17" y2="2" style="stroke-width:1.5" /> \
+    </g> \
+</svg>');
+}
+
+/* Append external link icon on all links starting with "http://" or "https://" */
+a[href^="http://"]::after, a[href^="https://"]::after {
+    content: '';
+    background: no-repeat var(--icon-external-link);
+    padding-right: 0.7em;
 }

docs/developers/hardware_ref/architecture.md

@@ -26,16 +26,14 @@ A 3D rendering of the PCBA done in KiCAD produces the images below:
 
 ## BOM
 
-An interactive BOM is available in the [next section][4].
+An interactive BOM is available in the [next section][1].
 
 ## Schematics and Layout
 
 All the hardware design and production files required to build the
-[**FunKey S** retro-gaming
+[**FunKey S** retro-gaming console][2] electronic PCBA using the
-console:fontawesome-solid-external-link-alt:][1] electronic PCBA using
+[KiCAD ECAD tools][3] are available as Open Hardware in the [FunKey S
-the [KiCAD ECAD tools:fontawesome-solid-external-link-alt:][2] are
+Hardware repository][4].
-available as Open Hardware in the [FunKey S Hardware
-repository:fontawesome-solid-external-link-alt:][3].
 
 ???+ note "Topological vs. logical schematic symbols"
 
@@ -70,10 +68,10 @@ repository:fontawesome-solid-external-link-alt:][3].
 The schematics will be discussed function by function in the following
 sections.
 
-[1]: https://www.funkey-project.com/
+[1]: https://htmlpreview.github.io/?https://github.com/FunKey-Project/FunKey-S-Hardware/blob/master/BOM/ibom.html
-[2]: https://kicad.org/
+[2]: https://www.funkey-project.com/
-[3]: https://github.com/FunKey-Project/FunKey-S-Hardware
+[3]: https://kicad.org/
-[4]: https://htmlpreview.github.io/?https://github.com/FunKey-Project/FunKey-S-Hardware/blob/master/BOM/ibom.html
+[4]: https://github.com/FunKey-Project/FunKey-S-Hardware
 
 --8<--
 includes/glossary.md

docs/developers/hardware_ref/audio.md

@@ -28,18 +28,16 @@ headphones either.
 ![Speaker](/assets/images/Speaker.png){: align=left }
 
 The best solution we have found consists in using a single tiny [CUI
-CDM-10008:fontawesome-solid-external-link-alt:][1] speaker, that is
+CDM-10008][1] speaker, that is able to output 72 dB spl @ 1m from a
-able to output 72 dB spl @ 1m from a 0.3W input power, with relatively
+0.3W input power, with relatively modest dimensions: 10 mm diameter
-modest dimensions: 10 mm diameter and only a 2.9 mm thickness, out of
+and only a 2.9 mm thickness, out of which 1.4 mm can be inserted into
-which 1.4 mm can be inserted into a PCB hole, thus only having a
+a PCB hole, thus only having a height above PCB of only 1.5 mm.
-height above PCB of only 1.5 mm.
 
 Connections are not easy though, since this speaker is meant to have
-wires soldered to its pads, but we used 2x
+wires soldered to its pads, but we used 2x [castellated][2]
-[castellated:fontawesome-solid-external-link-alt:][2] (half-round
+(half-round plated holes) pads with a placement just over the speaker
-plated holes) pads with a placement just over the speaker pads that
+pads that enables manual soldering between the speaker and the PCB
-enables manual soldering between the speaker and the PCB with a solder
+with a solder blob.
-blob.
 
 ## Schematic
 
@@ -48,11 +46,10 @@ contains an analog stereo audio codec (coder/decoder): we only have to
 take one of its headphone output channel (left or right) and feed it
 to a mono audio amplifier.
 
-We chose the [Diodes
+We chose the [Diodes Inc. PAM8301][3] chip because of its cheap price,
-Inc. PAM8301:fontawesome-solid-external-link-alt:][3] chip because of
+good availability, its more than sufficient output power of 1.5W and
-its cheap price, good availability, its more than sufficient output
+its filterless operation, meaning that no bulky series capacitor is
-power of 1.5W and its filterless operation, meaning that no bulky
+required to drive the speaker.
-series capacitor is required to drive the speaker.
 
 Here is the corresponding schematic:
 

docs/developers/hardware_ref/buttons.md

@@ -11,28 +11,26 @@ As can be seen in the page on the [PMIC][1], the soft "ON/OFF" button
 is directly connected to the power management chip, so we are left
 with 4 + 4 + 2 = 12 buttons for game control.
 
-After testing tactile domes in our [**FunKey
+After testing tactile domes in our [**FunKey Zero**][2] prototype, we
-Zero**:fontawesome-solid-external-link-alt:][2] prototype, we decided
+decided to go back to integrated tactile switches, as their placement
-to go back to integrated tactile switches, as their placement is much
+is much easier using a regular SMT pick & place machine like any other
-easier using a regular SMT pick & place machine like any other
 components on the PCB, whereas the separate tactile domes required an
 adhesive tape to be place manually with less accuracy.
 
 ![EVBPBB1AAB000](/assets/images/EVPBB1AAB000.png){: align=left }
 
-The [Mitsumi BYS-055A1x12:fontawesome-solid-external-link-alt:][3] is
+The [Mitsumi BYS-055A1x12][3] is the same footprint (2.5mm x 1.6mm x
-the same footprint (2.5mm x 1.6mm x 0.55mm) as the more expensive
+0.55mm) as the more expensive Panasonic EVBBBxAAB00 tactile switches,
-Panasonic EVBBBxAAB00 tactile switches, with a 1.2N actuating force
+with a 1.2N actuating force for the "**+**" and "**X**" pads, and a
-for the "**+**" and "**X**" pads, and a 1.6N actuating force for the
+1.6N actuating force for the "Start", "Fn" and "ON/OFF" buttons. We
-"Start", "Fn" and "ON/OFF" buttons. We found these actuating force the
+found these actuating force the best match to provide a good feedback
-best match to provide a good feedback to the user.
+to the user.
 
 ![EVP-AEBB2A-1](/assets/images/EVP-AEBB2A-1.jpg){: align=left }
 
 For the rear left and right shoulder buttons, we exeperimented several
 models between PCBA rev. C, D and E, until we eventually decided for a
-[replacement for the expensive Panasonic
+[replacement for the expensive Panasonic EVP-AEBB2A-1][4]:
-EVP-AEBB2A-1:fontawesome-solid-external-link-alt:][4]:
 
 This one as an actuating force of 1.6N.
 
@@ -59,11 +57,10 @@ PCB routing, at such a point that we decided to use a dedicated I2C
 GPIO expander chip to relieve the burden from the main V3s CPU.
 
 We use a common chip for this purpose, that is well supported in the
-Linux kernel: the [NXP
+Linux kernel: the [NXP PCAL6416AHF.128][5]. It is marketed as a
-PCAL6416AHF.128:fontawesome-solid-external-link-alt:][5]. It is
+"low-voltage translating 16-bit I2C-bus/SMBus I/O expander with
-marketed as a "low-voltage translating 16-bit I2C-bus/SMBus I/O
+interrupt output, reset, and configuration registers" that just
-expander with interrupt output, reset, and configuration registers"
+matches exactly our needs.
-that just matches exactly our needs.
 
 As a bonus, this chip features software-controlable internal
 pull-up/pull-down resistors, so we don't need to add external ones to

docs/developers/hardware_ref/cpu.md

@@ -4,16 +4,14 @@ As discussed in the [Design Constraints section][1], a CPU with
 external DRAM chips would take too much real-estate on the PCB, so we
 had to find a CPU with integrated DRAM.
 
-There are [several options:fontawesome-solid-external-link-alt:][2]
+There are [several options][2] for integrating RAM in a SoC:
-for integrating RAM in a SoC:
 
  - use SRAM: not possible because of the small amount of memory
    available (64Mbit max.)
 
  - embedded DRAM on the same chip: This is the solution used in the
-   [Apple M1 chip:fontawesome-solid-external-link-alt:][3], but this
+   [Apple M1 chip][3], but this chip is not available for retail and
-   chip is not available for retail and no other solutions seems
+   no other solutions seems readily available
-   readily available
 
  - Stacked Chip-on-Chip (PoP): This is the solution used on some
    Raspberry Pi boards, but this solution is only available for custom
@@ -23,17 +21,14 @@ for integrating RAM in a SoC:
  - DRAM die in SiP: with capacities ranging from 64Mbit to 1Gbit
 
 We found only 2 manufacturers providing the last option:
-[Microchip:fontawesome-solid-external-link-alt:][4] and [Allwinner
+[Microchip][4] and [Allwinner Technology][5]. Microchip solutions are
-Technology:fontawesome-solid-external-link-alt:][5]. Microchip
+too limited in term of CPU power for our needs (ARM926EJ-S or Cortex
-solutions are too limited in term of CPU power for our needs
+A5), so we did not consider them.
-(ARM926EJ-S or Cortex A5), so we did not consider them.
 
 And with the exception of the mostly similar Allwinner S3 CPU which
 features the same characteristics but with 128MB DDR3 DRAM in an
-FBGA234 package, the [Allwinner
+FBGA234 package, the [Allwinner V3s][6] is the CPU with integrated
-V3s:fontawesome-solid-external-link-alt:][6] is the CPU with
+DRAM having the highest memory capacity (512Mbit / 64MB DDR2 DRAM):
-integrated DRAM having the highest memory capacity (512Mbit / 64MB
-DDR2 DRAM):
 
 ![Allwinner V3s SoC](/assets/images/Allwinner_V3s.jpeg)
 
@@ -153,19 +148,16 @@ glitches.
 The SD Card interface is almost a direct connection between the chip
 and the dedicated SD Card connector. Only a single series resistor
 **R8** is required on the high-speed clock line in order to [prevent
-ringing:fontawesome-solid-external-link-alt:][7].
+ringing][7].
 
 ## Crystals
 
 The V3s chips requires 2 crystals:
 
- - one low-frequency [32.768 kHz
+ - one low-frequency [32.768 kHz crystal][8] **Y1** for the RTC clock
-   crystal:fontawesome-solid-external-link-alt:][8] **Y1** for the RTC
-   clock
 
- - one high-frequency [24 MHz
+ - one high-frequency [24 MHz crystal][9] **Y2** for deriving the 1.2
-crystal:fontawesome-solid-external-link-alt:][9] **Y2** for deriving
+GHz clock
-the 1.2 GHz clock
 
 The 24 MHz crystal is used by an internal oscillator to lock the phase
 of the 1.2 GHz oscillator using a PLL (Phase-Locked Loop).
@@ -183,21 +175,19 @@ The 32.768 kHz crystal features an additional high-value resistor
 thus reduce further the RTC timer power consumption.
 
 For more details on crystal oscillator design, please check [this
-application note from STM:fontawesome-solid-external-link-alt:][10].
+application note from STM][10].
 
 ## DRAM
 
-The DRAM within the V3s chip is a [DDR2
+The DRAM within the V3s chip is a [DDR2 one][11], meaning that its
-one:fontawesome-solid-external-link-alt:][11], meaning that its data
+data lines are clocked using both edges of an up to 400 MHz clock
-lines are clocked using both edges of an up to 400 MHz clock signal.
+signal.
 
 At these high frequencies, even short wires have a length that is of
-the same order of magnitude as the signal's
+the same order of magnitude as the signal's [wavelength][12] and thus
-[wavelength:fontawesome-solid-external-link-alt:][12] and thus each
+each signal should be considered as a [transmission line][13], for
-signal should be considered as a [transmission
+which impedance must be matched to avoid signal reflections, requiring
-line:fontawesome-solid-external-link-alt:][13], for which impedance
+termination resistors on the data lines DQx.
-must be matched to avoid signal reflections, requiring termination
-resistors on the data lines DQx.
 
 DDR2 or DDR3 DRAMs feature merged drivers and dynamic on-chip
 termination like this ("VDDQ/2" is labeled "SVREF" in our schematic):
@@ -211,8 +201,7 @@ resistor **R11** connected internally like this:
 ![Pull-Up Calibration](/assets/images/Pull-Up_Calibration.png){.lightbox}
 
 More information on the DDR2 DRAM ZQ Calibration subject can be found
-in this [Micron Application
+in this [Micron Application Note][14].
-Note:fontawesome-solid-external-link-alt:][14].
 
 [1]: /developers/hardware/design/#design-constraints
 [2]: https://www.electronicsweekly.com/news/products/memory/how-to-guide-for-on-chip-memory-2012-06/

docs/developers/hardware_ref/magnetic_switch.md

@@ -23,7 +23,7 @@ something quite usual for a keychain...
 
 We found only a unique plastic-molded model which almost meets our
 low-profile requirements of 1.5 mm (1.6 mm height!): the [Standex
-Meder MK24:fontawesome-solid-external-link-alt:][1].
+Meder MK24][1].
 
 Here is the corresponding schematics, already covered in the PMIC
 discussion:

docs/developers/hardware_ref/power/dc-dc.md

@@ -18,12 +18,11 @@ output voltage.
 
 ### Shunt Regulator
 
-The simplest voltage regulator is the [shunt
+The simplest voltage regulator is the [shunt regulator][1], built
-regulator:fontawesome-solid-external-link-alt:][1], built around a
+around a Zener diode which most interesting characteristic is to
-Zener diode which most interesting characteristic is to maintain a
+maintain a constant voltage across itself when the current through it
-constant voltage across itself when the current through it is
+is sufficient to take it into the Zener breakdown region. A simple
-sufficient to take it into the Zener breakdown region. A simple shunt
+shunt regulator looks like this:
-regulator looks like this:
 
 ![Zener Regulator](/assets/images/Zener_Regulator.gif)
 
@@ -33,8 +32,7 @@ By adding a emitter-follower transistor to the simple shunt regulator,
 the small base current of the transistor forms a very light load on
 the Zener, thereby minimizing variation in Zener voltage due to
 variation in the load, resulting in a better regulation. Here is a
-schematic for this [series
+schematic for this [series regulator][2]:
-regulator:fontawesome-solid-external-link-alt:][2]:
 
 ![Series Regualtor](/assets/images/Series_Regulator.gif)
 
@@ -122,14 +120,14 @@ following:
 ![Buck Converter](/assets/images/Buck_Converter.gif)
 
 The way this converter works is described in details
-[here:fontawesome-solid-external-link-alt:][3]. Basically, when the
+[here][3]. Basically, when the switch is closed, the inductor will
-switch is closed, the inductor will produce an opposing voltage across
+produce an opposing voltage across its terminals in response to the
-its terminals in response to the changing current, reducing the output
+changing current, reducing the output voltage, and meanwhile the
-voltage, and meanwhile the inductor stores this energy in the form of
+inductor stores this energy in the form of a magnetic field. When the
-a magnetic field. When the switch is opened, the current will decrease
+switch is opened, the current will decrease and will produce a voltage
-and will produce a voltage drop across the inductor, and now the
+drop across the inductor, and now the inductor becomes a current
-inductor becomes a current source, where the stored energy in the
+source, where the stored energy in the inductor's magnetic field is
-inductor's magnetic field is restored and fed to the load.
+restored and fed to the load.
 
 !!! warning
     In this converter too, the output voltage is not isolated from the

docs/developers/hardware_ref/power/decoupling.md

@@ -102,8 +102,7 @@ capacitors:
 One exception is the Allwinner V3s CPU HPR/HPL circuit which features
 an RC-to-ground circuit between the amplifier and the preamplifier
 input with the resistor **R27** and capacitors **C79** and **C81**, as
-recommended in the [V3s hardware design
+recommended in the [V3s hardware design guide][5].
-guide:fontawesome-solid-external-link-alt:][5].
 
 The only other remarkable point left in this schematic is the resistor
 divider **R25**/**R28** which provides a reference voltage at half the

docs/developers/hardware_ref/power/dram.md

@@ -1,5 +1,5 @@
-A separate [Sylergy SY8088:fontawesome-solid-external-link-alt:][1]
+A separate [Sylergy SY8088][1] Buck DC/DC SMPS chip is used to provide
-Buck DC/DC SMPS chip is used to provide the DDR2 +1V8 DDR2 DRAM power.
+the DDR2 +1V8 DDR2 DRAM power.
 
 This is because the AXP20x is originally the PMU (Power Management
 Unit) used by most Allwinner SoCs (A10, A13 and A20), which do not
@@ -15,7 +15,7 @@ We thus have to design a separate SMPS (DC-DC) power supply for
 providing the +1.8V 1A required for the DDR2 DRAM power supply.
 
 For this purpose, we followed closely the [Allwinner Reference
-Design:fontawesome-solid-external-link-alt:][2].
+Design][2].
 
 Here is the corresponding DRAM Power schematics:
 

docs/developers/hardware_ref/power/pmic.md

@@ -7,16 +7,14 @@ requirements to:
  - SMPS for +1.8V / 1A for the DDR2 DRAM power supply
  - SMPS for +1.25V / 1.6 A for the core power supply
 
-On the [LicheePi Zero board:fontawesome-solid-external-link-alt:][1]
+On the [LicheePi Zero board][1] used in our **[FunKey Zero][2]**
-used in our **[FunKey Zero:fontawesome-solid-external-link-alt:][2]**
+prototype, a triple SMPS [EA3036][3] is used for generating these
-prototype, a triple SMPS
++3.3V, +1.8V and +1.2V voltages, with an additional [XC6206][4] LDO
-[EA3036:fontawesome-solid-external-link-alt:][3] is used for
+for the +3.0V (the +3.3V Always On is connected directly to
-generating these +3.3V, +1.8V and +1.2V voltages, with an additional
++3.3V). Although compact (the EA3036 is a tiny 3 mm x 3 mm QFN20
-[XC6206:fontawesome-solid-external-link-alt:][4] LDO for the +3.0V
+package), this solution is not ideal as it does not provide a battery
-(the +3.3V Always On is connected directly to +3.3V). Although compact
+charger and monitoring capability, which is a requirement for the
-(the EA3036 is a tiny 3 mm x 3 mm QFN20 package), this solution is not
+**FunKey S** device.
-ideal as it does not provide a battery charger and monitoring
-capability, which is a requirement for the **FunKey S** device.
 
 ## PMICs
 
@@ -24,8 +22,7 @@ As it is generally the case with such a complex SoC requiring multiple
 voltages, high current and proper voltage sequencing, all major
 manufacturers provide dedicated companion chips called PMICs (Power
 Management Integrated Circuits), in charge of these tasks. Allwinner
-is not an exception through its sister company
+is not an exception through its sister company [X-Powers][5].
-[X-Powers:fontawesome-solid-external-link-alt:][5].
 
 Their AXP20x products are highly-integrated PMICs that are optimized
 for applications requiring single-cell Li-battery (Li-Ion/Polymer),
@@ -74,9 +71,7 @@ The AXP20x features:
    output to GPIO0)
 
 Looking at their datasheets, it is difficult to tell the difference
-between the [AXP202:fontawesome-solid-external-link-alt:][6],
+between the [AXP202][6], [AXP203][7] and [AXP209][8] (any hint
-[AXP203:fontawesome-solid-external-link-alt:][7] and
-[AXP209:fontawesome-solid-external-link-alt:][8] (any hint
 welcome!). In the **FunKey S** design, we use an AXP209 because it is
 the one that comes along with the V3s when you buy it on AliExpress.
 
@@ -88,8 +83,7 @@ the manufacturer, as the internals of the chips are seldom fully
 disclosed, so you need to take their word on some of the external
 component values to use.
 
-The [Allwinner V3s Reference
+The [Allwinner V3s Reference Design][9] contains on page 6 the
-Design:fontawesome-solid-external-link-alt:][9] contains on page 6 the
 schematics for using an AXP203 to supply the power to a V3s-based
 dashboard camera design. It follows closely the application diagram
 provided in the AXP20x datasheets:
@@ -97,7 +91,7 @@ provided in the AXP20x datasheets:
 ![AXP20x Application Diagram](/assets/images/AXP20x_Application_Diagram.png){.lightbox}
 
 More hints are provided in our self-translated [V3s Hardware Design
-Guide:fontawesome-solid-external-link-alt:][10] (page 7) too.
+Guide][10] (page 7) too.
 
 ## PMIC Schematics
 
@@ -173,11 +167,10 @@ operation:
 ### DC-DC1 PWM Battery Charger (North East side)
 
 The battery is connected to J5 (a [2-pin JST 1.0 mm pitch
-receptacle:fontawesome-solid-external-link-alt:][11]) and uses **R21**
+receptacle][11]) and uses **R21** as a precision current sense
-as a precision current sense resistor, with **C53**/**C56**/**C60**
+resistor, with **C53**/**C56**/**C60** filter capacitors and **L5** (a
-filter capacitors and **L5** (a low-profile ferrite-core power
+low-profile ferrite-core power inductor rated with a saturation
-inductor rated with a saturation current of 1.2A and low < 0.1 Ω
+current of 1.2A and low < 0.1 Ω resistance).
-resistance).
 
 !!! Warning
     The battery is not protected on the board against reversing
@@ -188,11 +181,10 @@ resistance).
 temperature, as the chosen LiPo battery does not feature this
 temperature sensor.
 
-A user-programmable (through the I2C interface) charge
+A user-programmable (through the I2C interface) charge [LED][12]
-[LED:fontawesome-solid-external-link-alt:][12] **D30** is provided,
+**D30** is provided, with its current-limiting resistor **R26**, as
-with its current-limiting resistor **R26**, as well as a TVS diode
+well as a TVS diode **d31** to prevent ESD, as the LED body will be
-**d31** to prevent ESD, as the LED body will be indirectly accessible
+indirectly accessible to user.
-to user.
 
 ### DC-DC2 +1.25V / 1.6A (West side)
 

docs/developers/hardware_ref/power/voltages.md

@@ -2,7 +2,7 @@ Looking back at the section on the [CPU schematics][1], the **FunKey
 S** device clearly needs a sophisticated power supply in order to
 fulfill the CPU power requirements. They are recalled below, along
 with the maximum current requirements found in the [Allwinner V3s
-reference design:fontawesome-solid-external-link-alt:][2] (page 3):
+reference design][2] (page 3):
 
  - +3.3V / 1.2A for the I/O power supply
  - +3.3V_AO / 30 mA for the Always-On power supply (RTC timer)

docs/developers/hardware_ref/screen.md

@@ -52,9 +52,8 @@ RGB565 (2 bytes / pixel), this requires a ~44 MHz SPI clock rate,
 which is rather high.
 
 Once again, we were fortunate as both the V3s CPU and the screen
-built-in controller (a Sitronix
+built-in controller (a Sitronix [ST7789V][1]) both support this high
-[ST7789V:fontawesome-solid-external-link-alt:][1]) both support this
+clock speed (after checking with the manufacturer and despite the
-high clock speed (after checking with the manufacturer and despite the
 controller datasheet that specifies only a serial clock cycle (Write)
 of 66 ns or 15 MHz!).
 
@@ -66,8 +65,8 @@ current directly from a CPU GPIO and the backlight will require an
 additional transistor to interface to the LCD backlight.
 
 Its flex cable requires a mating Hirose 0.4 mm pitch
-[DF37NB-24DS-0.4V:fontawesome-solid-external-link-alt:][2] dual row
+[DF37NB-24DS-0.4V][2] dual row SMT connector, out of which only one
-SMT connector, out of which only one single row is actually used.
+single row is actually used.
 
 ## Customization
 
@@ -75,10 +74,9 @@ Unfortunately, the flex cable for the stock LCD screen we found does
 not match our particular **FunKey S** mechanical design.
 
 For the prototypes, we designed custom flex extension cables for a ~
-$100 cost, but we had to design [our own custom
+$100 cost, but we had to design [our own custom flex][3] and have this
-flex:fontawesome-solid-external-link-alt:][3] and have this standard
+standard screen assembly attached to it for mass production, with a
-screen assembly attached to it for mass production, with a one-time
+one-time tooling fee of ~ $800.
-tooling fee of ~ $800.
 
 ## Schematic
 

docs/developers/hardware_ref/sd-card.md

@@ -16,17 +16,14 @@ the specifications.
 
 The SD Card physical interface is provided in the "<i>SD
 specifications, part 1, Physical Layer Specification version 2.00, May
-9, 2006</i>", for which a simplified version is available
+9, 2006</i>", for which a simplified version is available [here][1].
-[here:fontawesome-solid-external-link-alt:][1].
 
 The MMC phyiscal interface can be found in the "<i>Multi Media Card
 System Specification version 4.3, JESD84-A43, November 2007</i>",
-available [here:fontawesome-solid-external-link-alt:][2] (registration
+available [here][2] (registration required).
-required).
 
-But a good summary of the requirements is given in the "[<i>AN10911
+But a good summary of the requirements is given in the "_[AN10911
-SD(HC)-memory card and MMC Interface
+SD(HC)-memory card and MMC Interface conditioning][3]_" application
-conditioning</i>:fontawesome-solid-external-link-alt:][3]" application
 note from NXP, from which this schematic is taken:
 
 ![SD MMC Interface](/assets/images/SD_MMC_Interface.png){.lightbox}
@@ -88,9 +85,9 @@ The FunKey SD Card interface schematic is the following:
 ![TF-110](/assets/images/TF-110.png){: align=left }
 
 As can be expected, the main component is the [Micro SD (TF Card)
-Push/Pull connector:fontawesome-solid-external-link-alt:][5] **J4**,
+Push/Pull connector][5] **J4**, which has been selected for its
-which has been selected for its low-profile (1.3 mm height)
+low-profile (1.3 mm height) characteristic and overall minimal
-characteristic and overall minimal dimensions.
+dimensions.
 
 !!! Tip
 

docs/developers/hardware_ref/usb.md

@@ -14,12 +14,11 @@ the cable wiring which role we must take.
 
 ![U02-BFD3111B0-009](/assets/images/U02-BFD3111B0-009.png){: align=left }
 
-The main part is of course the [Micro USB edge-mounted
+The main part is of course the [Micro USB edge-mounted connector][1]
-connector:fontawesome-solid-external-link-alt:][1] **J2**, which we
+**J2**, which we chose in order to "mask out" its already low-profile
-chose in order to "mask out" its already low-profile height into the
+height into the PCB thickness. And with its "harpoon-like"
-PCB thickness. And with its "harpoon-like" through-hole legs, it
+through-hole legs, it should avoid tearing it off the board if the
-should avoid tearing it off the board if the user don't pull the chord
+user don't pull the chord straight.
-straight.
 
 The USB schematic is the following:
 
@@ -43,12 +42,10 @@ maximum bulk capacitance value to 10 µF in order to avoid power supply
 excessive droops when plugin in a device with a discharged large bulk
 capacitor.
 
-**D15** is a [NXP
+**D15** is a [NXP PRTR5V0U2X,215][2] combined TVS protection diode for
-PRTR5V0U2X,215:fontawesome-solid-external-link-alt:][2] combined TVS
+the VBUS pin and a set of clamping diodes that will limit the voltage
-protection diode for the VBUS pin and a set of clamping diodes that
+on D+ and D- pins to stay between GND and VBUS levels to in order to
-will limit the voltage on D+ and D- pins to stay between GND and VBUS
+protect the V3s USB driver from under / over-voltages.
-levels to in order to protect the V3s USB driver from under /
-over-voltages.
 
 [1]: https://github.com/FunKey-Project/FunKey-S-Hardware/blob/master/Datasheets/C40958_MICRO5P%E6%B2%89%E6%9D%BF%E5%BC%8F0.8%E5%9B%9B%E8%84%9A%E5%85%A8%E6%8F%92%E6%97%A0%E5%AF%BC%E4%BD%8D%E6%9C%89%E5%AD%94%E8%80%90%E9%AB%98%E6%B8%A9_2016-05-20.PDF
 [2]: https://github.com/FunKey-Project/FunKey-S-Hardware/blob/master/Datasheets/C12333_PRTR5V0U2X%2C215_2017-10-31.PDF

docs/tutorials/hardware/change_sd_card.md

@@ -10,17 +10,17 @@ your data.
 ## Download the latest FunKey-OS image file
 
 Get the latest "***FunKey-rootfs-x.y.z.img***" SD card image file
-directly from [here:fontawesome-solid-external-link-alt:][1] or from
+directly from [here][1] or from the bottom of the latest release page
-the bottom of the latest release page in the "assets" section:
+in the "assets" section:
 
-[https://github.com/FunKey-Project/FunKey-OS/releases/latest:fontawesome-solid-external-link-alt:][2]{target=_blank}
+[https://github.com/FunKey-Project/FunKey-OS/releases/latest][2]{target=_blank}
 
 ![Github Release](/assets/images/github_sd_card_image.png){.lightbox}
 
 ## Flash the micro-SD card with balenaEtcher
 
 - Download and install balenaEtcher for Windows/Mac OS/Linux from
-  [balena.io:fontawesome-solid-external-link-alt:][3]{:target="blank"}
+  [balena.io][3]{target=_blank}
 
 - Run balenaEtcher and click on "Flash from file" to select the
   FunKey-OS image file

docs/tutorials/software/add_roms.md

@@ -4,13 +4,10 @@ Yes legally! Despite the general opinion, it is perfectly possible to
 purchase and play famous ROMs legally such as Sonic, Castlevania,
 Megaman and more, read the note below for more details.
 
-**The FunKey Wiki** maintains
+**The FunKey Wiki** maintains [lists][1]{target=_blank} of legal
-[lists:fontawesome-solid-external-link-alt:][1]{target=_blank} of
+sources for ROMs, including [freeware ROMs][2]{target=_blank},
-legal sources for ROMs, including [freeware
+[commercial ROMs][3]{target=_blank}, and
-ROMs:fontawesome-solid-external-link-alt:][2]{target=_blank},
+[utilities][4]{target=_blank}.
-[commercial
-ROMs:fontawesome-solid-external-link-alt:][3]{target=_blank}, and
-[utilities:fontawesome-solid-external-link-alt:][4]{target=_blank}.
 
 !!! note "Note about ROM emulation"
 
@@ -29,7 +26,7 @@ ROMs:fontawesome-solid-external-link-alt:][3]{target=_blank}, and
     retro-games online as ROMs.
 
     For example, it is perfectly legal to purchase the SEGA Mega Drive
-    and Genesis Classics on [Steam][5]{:target="blank"} and play Sonic
+    and Genesis Classics on [Steam][5]{target=_blank} and play Sonic
     on your **FunKey S**.
 
 # Add ROMs to the FunKey S

docs/tutorials/software/copy_opk.md

@@ -8,11 +8,9 @@ does not require installation to be able to run them.
     In the current (2.0.0) release of the FunKey-OS, the **OPK** files
     are only available for the gmenu2x launcher, and not in RetroFE.
 
-[7-Zip:fontawesome-solid-external-link-alt:][1] can be used to extract
+[7-Zip][1] can be used to extract **OPK** files, and [Open Package
-**OPK** files, and [Open Package Creator
+Creator (v1.1.2)][2] is a useful tool if you want to re-package an
-(v1.1.2):fontawesome-solid-external-link-alt:][2] is a useful tool if
+**OPK** or customize icons, add additional games and much more.
-you want to re-package an **OPK** or customize icons, add additional
-games and much more.
 
 Connect your **FunKey S** console to your computer and add **OPK**
 files as simply as you would do it with a simple USB memory stick:

docs/tutorials/software/gb_palette.md

@@ -1,9 +1,8 @@
 # Palette description
 
-The default **FunKey S** Game Boy emulator:
+The default **FunKey S** Game Boy emulator: _[gnuboy][1]_ allows to
-_[gnuboy:fontawesome-solid-external-link-alt:][1]_ allows to set the
+set the palette used for grayscale when running DMG (original mono
-palette used for grayscale when running DMG (original mono Gameboy)
+Gameboy) ROMs.
-ROMs.
 
 There are four variables for this purpose, allowing the background,
 window, and both sprite palettes to be colored differently. Each one

docs/tutorials/software/update.md

@@ -2,10 +2,10 @@ A firmware upgrade can be performed simply over USB without opening
 the **FunKey S** console.
 
 Get the latest "**_FunKey-rootfs-x.y.z.fwu_**" firmware update file
-directly from [here:fontawesome-solid-external-link-alt:][1] or from
+directly from [here][1] or from the bottom of the latest release page
-the bottom of the latest release page in the "assets" section:
+in the "assets" section:
 
-[https://github.com/FunKey-Project/FunKey-OS/releases/latest:fontawesome-solid-external-link-alt:][2]{target=_blank}
+[https://github.com/FunKey-Project/FunKey-OS/releases/latest][2]{target=_blank}
 
 ![Github Release](/assets/images/Github_Release.png){.lightbox}