I2S driver + Basic Audio sample (#1862)

* I2S driver

* Arduino I2S compatibility layer

* Add `MinMaxTimes` class template, `MinMax32` and `CpuUsage` to Profiling

Also update linker script so times can be used in interrupt context

* Add `GDB_UART_SWAP` option

* Add SignalGenerator library

* Basic Audio sample

* Fix codacy issues

Sming/Arch/Esp8266/Compiler/ld/common.ld

@@ -2,6 +2,8 @@
     common.ld
 */
 
+INCLUDE "peripherals.ld"
+
 PHDRS
 {
   dport0_0_phdr PT_LOAD;
@@ -128,6 +130,7 @@ SECTIONS
 	*(.literal._ZN13CallbackTimer*)
 	*(.text._ZN13CallbackTimer*)
     *(.text._ZNKSt8functionIF*EE*)  /* std::function<any(...)>::operator()() const */
+	*(.text._ZN9Profiling6MinMaxIjE6updateEj)
 
   } >iram1_0_seg :iram1_0_phdr
 

Sming/Arch/Esp8266/Compiler/ld/peripherals.ld

@@ -0,0 +1,18 @@
+/*
+ * From RTOS SDK
+ */
+
+PROVIDE ( GPIO = 0x60000300);
+
+PROVIDE ( uart0 = 0x60000000 );
+PROVIDE ( uart1 = 0x60000f00 );
+
+PROVIDE ( frc1 = 0x60000600 );
+
+PROVIDE ( rtc_sys_info = 0x60001100 );
+
+PROVIDE ( SLC0 = 0x60000B00 );
+PROVIDE ( I2S0 = 0x60000e00 );
+
+PROVIDE ( SPI1 = 0x60000100 );
+PROVIDE ( SPI0 = 0x60000200 );

Sming/Arch/Esp8266/Components/driver/README.rst

@@ -7,6 +7,10 @@ Provides low-level peripheral drivers.
 * PWM: Common header for PWM support
 * hw_timer: Driver for hardware timers
 
+.. toctree::
+
+   i2s
+
 hw_timer
 --------