primitives/tests/adctest.py

   1 # adctest.py
   2
   3 # Copyright (c) 2020 Peter Hinch
   4 # Released under the MIT License (MIT) - see LICENSE file
   5
   6 import uasyncio as asyncio
   7 from machine import ADC
   8 import pyb
   9 from primitives import AADC
  10
  11 async def signal():  # Could use write_timed but this prints values
  12     dac = pyb.DAC(1, bits=12, buffering=True)
  13     v = 0
  14     while True:
  15         if not v & 0xf:
  16             print('write', v << 4)  # Make value u16 as per ADC read
  17         dac.write(v)
  18         v += 1
  19         v %= 4096
  20         await asyncio.sleep_ms(50)
  21
  22 async def adctest():
  23     asyncio.create_task(signal())
  24     adc = AADC(ADC(pyb.Pin.board.X1))
  25     await asyncio.sleep(0)
  26     adc.sense(normal=False)  # Wait until ADC gets to 5000
  27     value =  await adc(5000, 10000)
  28     print('Received', value, adc.read_u16(True))  # Reduce to 12 bits
  29     adc.sense(normal=True)  # Now print all changes > 2000
  30     while True:
  31         value = await adc(2000)  # Trigger if value changes by 2000
  32         print('Received', value, adc.read_u16(True))
  33
  34 st = '''This test requires a Pyboard with pins X1 and X5 linked.
  35 A sawtooth waveform is applied to the ADC. Initially the test waits
  36 until the ADC value reaches 5000. It then reports whenever the value
  37 changes by 2000.
  38 Issue test() to start.
  39 '''
  40 print(st)
  41
  42 def test():
  43     try:
  44         asyncio.run(adctest())
  45     except KeyboardInterrupt:
  46         print('Interrupted')
  47     finally:
  48         asyncio.new_event_loop()
  49         print()
  50         print(st)