Mic api test

en/api-reference/mic/mic.rst

@@ -0,0 +1,45 @@
+# Usage
+
+.. code:: python
+
+	from m5stack import *
+	import machine, _thread
+
+	mic_adc = 0
+	buffer = []
+	def microphone_enter():
+		print('microphone_enter')
+  		global mic_adc, buffer
+  		try:
+  			mic_adc = machine.ADC(34)
+  			mic_adc.atten(mic_adc.ATTN_11DB)
+    		dac = machine.DAC(machine.Pin(25))
+    		dac.write(0)
+  		except:
+  			pass
+  		buffer = []
+  		for i in range(0, 55):
+  			buffer.append(0)
+
+
+	def microphone_loop():
+		global mic_adc, buffer
+  		val = 0
+  		for i in range(0, 32):
+  			raw = (mic_adc.readraw() - 1845) // 10
+    		if raw > 20:
+      			raw = 20
+    		elif raw < -20:
+      			raw = -20
+    		val += raw
+    	val = val // 32
+  		buffer.pop()
+  		buffer.insert(0, val)
+  		for i in range(1, 50):
+    		lcd.line(i*2+44, 120+buffer[i+1], i*2+44+2, 120+buffer[i+2], lcd.WHITE)
+    		lcd.line(i*2+44, 120+buffer[i],   i*2+44+2, 120+buffer[i+1], lcd.BLACK)
+
+	microphone_enter()
+
+	while 1:
+		microphone_loop()