Replace |I2S| and |I2C| with their superscripted versions

doc/rst/lib_board_support.rst

@@ -61,12 +61,12 @@ the relevant header file. For example::
 From then onwards the code may call the relevant API functions to setup and configure the board
 hardware. Examples are provided in the `examples` directory of this repo.
 
-Note that in some cases, the `xcore` tile that calls the configuration function (usually from |I2S|
-initialisation) is different from the tile where |I2C| master is placed. Since |I2C| master is
+Note that in some cases, the `xcore` tile that calls the configuration function (usually from I²S
+initialisation) is different from the tile where I²C master is placed. Since I²C master is
 required by most audio CODECs for configuration and `xcore` tiles can only communicate with each
-other via channels, a remote server is needed to provide the |I2C| setup. This usually takes the
-form of a task which is run on a thread placed on the |I2C| tile and is controlled via a channel
-from the other tile where |I2S| resides. The cross-tile channel must be declared at the top-level
+other via channels, a remote server is needed to provide the I²C setup. This usually takes the
+form of a task which is run on a thread placed on the I²C tile and is controlled via a channel
+from the other tile where I²S resides. The cross-tile channel must be declared at the top-level
 XC main function. The included examples provide a reference for this using both XC and C.
 
 ********************************
@@ -133,8 +133,8 @@ application where the hardware setup is called from C.
 
 These applications run on the `XK-EVK-XU316` and `XK-AUDIO-316-MC` boards respectively.
 
-They show how to use the cross-tile communications in conjunction with the |I2C| master server.
-The applications only setup the hardware and then exit the |I2C| server.
+They show how to use the cross-tile communications in conjunction with the I²C master server.
+The applications only setup the hardware and then exit the I²C server.
 
 XC Usage Example
 ================

doc/rst/xk_audio_216_mc_ab/hw_216_mc.rst

@@ -22,7 +22,7 @@ Analogue Input & Output
 A total of eight single-ended analog input channels are provided via 3.5mm stereo jacks. Each is fed into a CirrusLogic CS5368 ADC.
 Similarly a total of eight single-ended analog output channels are provided. Each is fed into a CirrusLogic CS4384 DAC.
 
-The four digital |I2S|/TDM input and output channels are mapped to the `xcore` input/outputs through a header array. This jumper allows channel selection when the ADC/DAC is used in TDM mode
+The four digital I²S/TDM input and output channels are mapped to the `xcore` input/outputs through a header array. This jumper allows channel selection when the ADC/DAC is used in TDM mode
 
 Digital Input & Output
 ----------------------

doc/rst/xk_audio_316_mc_ab/hw_316_mc.rst

@@ -51,9 +51,9 @@ It includes the following features:
 
 - M: 3 general purpose buttons
 
-- O: Flexible |I2S|/TDM input data routing
+- O: Flexible I²S/TDM input data routing
 
-- P: Flexible |I2S|/TDM output data routing
+- P: Flexible I²S/TDM output data routing
 
 - Q: Integrated power supply
 
@@ -71,9 +71,9 @@ A total of eight single-ended analog input channels are provided via 3.5mm stere
 
 A total of eight single-ended analog output channels are provided. These are fed from four PCM5122 stereo DAC's from Texas instruments.
 
-All ADC's and DAC's are configured via an |I2C| bus. Due to an clash of device addresses a |I2C| multiplexor is used.
+All ADC's and DAC's are configured via an I²C bus. Due to an clash of device addresses a I²C multiplexor is used.
 
-The four digital |I2S|/TDM input and output channels are mapped to the xCORE input/outputs through a header array. These jumpers allow channel selection when the ADCs/DACs are used in TDM mode.
+The four digital I²S/TDM input and output channels are mapped to the xCORE input/outputs through a header array. These jumpers allow channel selection when the ADCs/DACs are used in TDM mode.
 
 Digital Input & Output
 ----------------------
@@ -98,7 +98,7 @@ Three methods of generating an audio master clock are provided on the board:
 
     * A Cirrus Logic CS2100-CP PLL device.  The CS2100 features both a clock generator and clock multiplier/jitter reduced clock frequency synthesizer (clean up) and can generate a low jitter audio clock based on a synchronisation signal provided by the `xcore`
 
-    * A Skyworks Si5351B PLL device. The Si5351 is an |I2C| configurable clock generator that is suited for replacing crystals, crystal oscillators, VCXOs, phase-locked loops (PLLs), and fanout buffers.
+    * A Skyworks Si5351B PLL device. The Si5351 is an I²C configurable clock generator that is suited for replacing crystals, crystal oscillators, VCXOs, phase-locked loops (PLLs), and fanout buffers.
 
     * `xcore.ai` devices are equipped with a secondary (or `application`) PLL which can be used to generate audio clocks.
 

doc/rst/xk_evk_xu316/hw_evk_xu316.rst

@@ -38,10 +38,10 @@ For full details regarding the hardware please refer to `XK-EVK-XU316 xcore.ai E
 Analogue Audio Input & Output
 -----------------------------
 
-A stereo CODEC (TLV320AIC3204), connected to the xcore.ai device via an |I2S| interface, provides analogue input/output
+A stereo CODEC (TLV320AIC3204), connected to the xcore.ai device via an I²S interface, provides analogue input/output
 functionality at line level.
 
-The audio CODEC is are configured by the `xcore.ai` device via an |I2C| bus.
+The audio CODEC is are configured by the `xcore.ai` device via an I²C bus.
 
 Audio Clocking
 --------------