16bit resolution PWM wave player with SD card, super lite version.

Dependencies:   mbed DirectSPI FastPWM

Supported boards (confirmed):
Nucleo-F030R8
Nucleo-L152RE
Nucleo-F401RE
Nucleo-F411RE

Only compilation is OK (unchecked, but may work):
Nucleo-L073RZ
Nucleo-F334R8
Nucleo-F303RE
Nucleo-F429ZI
Nucleo-F446RE
Nucleo-F446ZE
Nucleo-L476RG

Supported SD card:
SDSC/SDHC card,
FAT16 and FAT32.
(1) At first, format SD card using SD Card Formatter
https://www.sdcard.org/downloads/formatter_4/index.html
(2) Copy PCM wav files to the SD card.
Supported file:
PCM wave file that have file extension ".wav" on root directory.
16bit/8bit, fs(sampling rate)=32kHz,44.1kHz,48kHz.
Stereo/Mono.

Hardware setting:
Refer to the file port_setting.txt
PWM output port:
Left upper(Hi) PWM 8bit out: PB_5 (TM3_CH2)
Right upper(Hi) PWM 8bit out: PB4 (TM3_CH1)
Left lower(Low) PWM 8bit out: PC_9 (TM3_CH4)
Right lower(Low) PWM 8bit out: PC_8 (TM3_CH3)
http://mpu.up.seesaa.net/image/16bit-wave-player-output-schema.png
USER_BUTTON: PC_13(default button)
Next song: One click in Play mode.
Pause : Push long time .
Play : One click from Pause.

Revision:
16:1bb81504b23b
Parent:
11:8dc9fa1e1bdc
--- a/sys.h	Sun Feb 17 11:48:22 2019 +0900
+++ b/sys.h	Sun Feb 17 11:59:16 2019 +0900
@@ -14,15 +14,15 @@
 ----------------------*/
 #define PWM16BIT                     1
 #define DATA_8BIT_SUPPORT            1
-#define HAVE_BUTTON_SW               1  //; for 'Play','Pause','Power off'
+#define HAVE_BUTTON_SW               1  // for 'Play','Pause','Power off'
 /* Enable either the type of blink or dimmer  */
-#define HAVE_LED_IND_PWM             1  //; blink  LED during playing (750msec interval)
-#define HAVE_LED_IND_BLINK           0  //; dimmer LED during playing
+#define HAVE_LED_IND_PWM             1  // blink  LED during playing (750msec interval)
+#define HAVE_LED_IND_BLINK           0  // dimmer LED during playing
 /**********************/
-#define HAVE_LED_PAUSE_INDICATOR     1  //; blink or dimmer during pausing
-#define HAVE_POWER_OFF_MODE          0  //; under construction
+#define HAVE_LED_PAUSE_INDICATOR     1  // blink or dimmer during pausing
+#define HAVE_POWER_OFF_MODE          0  // under construction
 //-- Select FAT32/FAT16 or FAT16 only
-#define HAVE_FAT32                   1  //; false: FAT16 only, true: FAT16 and FAT32 support
+#define HAVE_FAT32                   1  // 0: FAT16 only, 1: FAT16 and FAT32 support
 //--- end option setting
 
 // TEST PORT