使用ESP32读取数字硅麦的数据

Posted 2022-11-26 卓晴

测试硅麦的输出数据

 

01 数字硅麦

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一、背景介绍

  手边的这个数字硅麦， 是来自Infineon提供的样品， 它的接口是PDM输出。 在前面已经对该传感器进行过初步的测试。 现在使用ESP32平台来读取该它的输出信号。 根据测试，硅麦要求时钟信号大于400kHz， 利用ESP32的SPI接口可以输出超过这个频率的时钟信号， 同时可以读入相应的数据。

二、ESP32输入输出

1、测试SPI脉冲

  根据 WS2812串行可控彩色LED灯珠 中的测试程序。 编写SPI基本测试脉冲程序。 通过管脚14输出时钟信号， 时钟频率为2.5MHz。 这是测量ESP32第12管脚输出波形， 可以看到对应的周期为400ns，频率为2.5MHz。

from machine                import Pin,Timer,SPI
import time

hspi = SPI(1, 2500000, sck=Pin(14), 
           mosi=Pin(13), miso=Pin(12), polarity=0)

outbyte = bytes([0xff]*16)

print("Test.")
while True:
    hspi.write(outbyte)
    time.sleep_ms(10)

▲ 图1.2.1 SPI管脚分布

  下面将SPI 输出频率修改成500KHz，  输入输出2000个字节。 这是测量硅麦PDM输出波形。 下面看看其中脉冲结构。 前面1ms是芯片启动。 这部分是内部稳定时输出信号 这里可以看到输出带有信号的波形。 

from machine                import Pin,Timer,SPI
import time

hspi = SPI(1, 500000, sck=Pin(14),
           mosi=Pin(13), miso=Pin(12), polarity=0)

print("Test.")
while True:
    readb = hspi.read(2048)
    time.sleep_ms(1)
    break

print(readb)

b"\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xff\\xfdUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU&\\xb2\\xa7*\\xaa\\xc9\\xca\\xac\\x9c\\xab*\\xb2\\xaa\\xb3)\\xd2\\xb2t\\xaa\\xd2\\xaa\\xd2\\xabJ\\xb3+,\\xad+-*\\xb5*\\xd2\\xb4\\xb2\\xcbL\\xad+L\\xca\\xd2\\xd2\\xcc\\xb4\\xcb2\\xd32\\xd2\\xb4\\xcc\\xb4\\xcb3-J\\xb52\\xb4\\xb3K-2\\xb4\\xb4\\xad2\\xadQ\\xb4\\xca\\xd2\\xb4\\xabK,\\xad*\\xcbJ\\xabL\\x9d*\\xb3+)\\xd3\\x1c\\xab*\\xac\\xac\\x9c\\xab&\\xcb\\x1a\\xc9\\xb2\\xa7,\\\\\\xa9\\xca\\x9b&\\xaa\\xa9\\xb1\\x9c\\x9a\\xa9\\xaa\\xa6\\x9a\\xaa\\x96\\xaaji\\xa9\\xa9\\x9a\\xa6f\\xa9i\\xa9\\x9aZ\\x96\\xa6Z\\x99i\\xa5j\\x95\\xa5\\xa5\\xa9V\\xa9V\\x99iiZV\\xa5fe\\x99\\x96e\\xa5ifY\\x96\\x96e\\x99iiZY\\xa5\\x99i\\x96\\x99\\x96\\x99\\x99\\x9a\\x95\\xa6\\x96\\xa9\\x96ji\\x9a\\x96\\xaaZj\\xa5\\xb1i\\xb1\\x9a\\xaag\\x1a\\xaa\\xa6\\xa9\\xb2\\x9a\\xc6\\xaa\\xb1\\x9c\\xc6\\xb2l\\xaa\\xb2l\\xc9\\xb3'1\\xcb*\\xca\\xca\\xb3*\\xcb,\\xb2\\xad,\\xb2\\xb32\\xcb2\\xcc\\xb4\\xac\\xcd+4\\xb2\\xd4\\xac\\xcd2\\xd2\\xcc\\xd4\\xaba\\xd4\\xadR\\xb4\\xcd2\\xd34\\xcc\\xb52\\xd4\\xadL\\xcc\\xcd-2\\xd4\\xb33KK4\\xb3J\\xd32\\xcc\\xd2\\xac\\xd3,\\xb3+J\\xcc\\xca\\xb2\\xd2\\xac\\xca\\xad*\\xb2\\xb3)\\xcc\\xaa\\xca\\xac\\xa72\\x9b,j\\xb2l\\x9b&\\xc6\\xc6\\xaal\\x9a\\xa7\\x1a\\x9a\\xc5\\xaa\\xa5\\xc6\\x9a\\x9a\\xa6jf\\xa9i\\xa9\\x9aZ\\x96\\xa5\\xa6Z\\x96fffe\\x99i\\x95\\x96\\x96eZYe\\x95\\x96eYe\\x95\\x95fUZUeYYU\\x96UVYUe\\x93\\x96UeYVUYeYUe\\x98\\xe5YeeY\\x95ee\\xa3\\x99ee\\x99fVZYf\\x95i\\x99\\x96\\x96fi\\x99\\x96\\x9af\\x96\\x9aiji\\xa6i\\xa9\\xa6\\xa6\\x9a\\x9a\\x99\\xc6\\xa6\\x9a\\xaa\\x99\\xab\\x16\\xaa\\x9a\\xc6lj\\xa9\\xacj\\xa9\\xc9\\xb1\\xb1\\xacj\\x9d\\x1a\\xacj\\xc6\\xac\\x9c\\x9c\\xaa\\xc6\\xb2l\\xc6\\xab'1\\xac\\xa71\\xac\\xaa\\xc9\\xac\\xac\\x9b*\\xac\\x9c\\xaa\\xb2r\\xaa\\xab*\\xa71\\xab'\\x1c\\xa7*\\xa9\\xca\\xaa\\x9b)\\xacj\\xaa\\x9a\\xaa\\xaai\\xc6\\xc5\\xb1\\x9a\\xa9\\xa6\\xc6f\\xaai\\x9a\\xa6\\x96\\xa9\\xa5\\x9a\\xa5\\xa6ii\\x99\\x9aY\\x99\\x96\\x96fYfV\\x95\\x99YY\\x95efNYYUVd\\xd9UVT\\xe5U\\x8d:5X\\xcd\\x95SUUMX\\xd3X\\xce5T\\xd5ST\\xd63U6-V+d\\xd5MMb\\xd5T\\xd4\\xd8\\xd4\\xd8\\xcdX\\xd3UUMT\\xe55cNM\\x94\\xd5ccUX\\xd95\\x95S\\xa4\\xd9UVUd\\xe6NYUh\\xe5Y\\x95VZT\\xf1UieZYY\\x96eifYie\\xa6V\\xa5iii\\x96i\\x96\\x9aY\\xa5\\xa9i\\x96\\xa9ii\\xa6\\x99\\x9a\\x96\\x9a\\x96\\xa9\\\\fji\\x9a\\x96\\xaaZf\\xaae\\xa9\\xa9\\xa6jf\\x9a\\xa5\\xa6\\x9a\\x96\\xa9jfji\\x99\\xa6i\\xa6iij\\x95\\xa9Z\\x99\\x96iiZ\\x95\\x99\\x99Z\\x8e\\x95\\x99\\x95\\xa3\\xa5Y\\x96UfU\\x966\\x93iNYNV6T\\xe5Uc9UT\\xd65T\\xd5T\\xd55T\\xcdT\\xd4\\xcdT\\xcc\\xd4\\xd3L\\xd3L\\xcd4\\xb3KR\\xcc\\xb5+K-J\\xb3J\\xd2\\xad,\\xca\\xb2\\xd2\\xca\\xad,\\xaa\\xcc\\xb2\\xac\\xb2\\xab2\\xb2\\x9d2\\xa7L\\x9c\\xb2\\xac\\xac\\x9d*\\xca\\xabJt\\xaa\\xb4\\x9c\\xca\\xb2\\xac\\xb2\\xabJ\\xac\\xac\\xb3*\\xac\\xd2\\xac\\xac\\xcb2\\xabR\\xb2\\xcbJ\\xd2\\xb4\\xb32\\xcd,\\xb4\\xd2\\xb3R\\xd3,\\xd4\\xcbS4\\xb53M4\\xd3553MT\\xcd5SMMT\\xd3US5U5MUMN5UM6MUSUT\\xe3UT\\xe3X\\xb9SX\\xd5S\\x93U\\x8d8\\xe4\\xd4\\xe5T\\xd5T\\xd95ScUMT\\xd8\\xd5K\\x93UR\\xd8\\xd3U3X\\xb4\\xd4\\xd5.-M3T\\xb4\\xcdL\\xb5333KKJ\\xd3,\\xcb3*\\xcd*\\xb4\\xab,\\xaa\\xcb*\\xb2\\xaa\\xb2\\xab\\x1a\\xcar\\x9c\\xa9\\xcaj\\xaa\\xaajlf\\xc6j\\x9aj\\x9ai\\x9a\\xa5\\xa9\\xa5\\x9a\\x99\\xa5\\x9aZffZY\\x99iZee\\xa5\\x96efYe\\xa3\\x99\\x95iVefU\\xa5VfU\\x99Ve\\x95\\x99Ve\\x96VeiU\\xa6U\\xa5fYe\\x99\\x95\\x99\\x96eiiY\\x99\\x99fe\\xa5\\xa6ZV\\xa6ZZifjZfi\\xa6f\\x9a\\x96\\x9a\\x99\\x9a\\xa9\\\\i\\xa6\\x9a\\x9a\\x9a\\x9ai\\xb1j\\x9a\\x9a\\xa9\\x9a\\xc5\\xacY\\xcajj\\xaa\\x97&\\xa7&\\xa9\\xb1\\xa6\\xb1\\xa6\\xc6\\xaaj\\xaa\\xa9\\x9c\\xa9\\xaa\\xaa\\xa6\\xa9\\xb1\\xc6\\x9c\\x9a\\xaali\\xb2jk\\x19\\xb1\\xa9\\xaa\\xa9\\x9b%\\xc6\\x9cf\\xaai\\xaai\\xaa\\x96\\x9a\\xa9jf\\xa6i\\xa9f\\xa5\\xa9ijY\\xa5\\xa5\\xa5\\x99\\x99iZYfeV\\xa5d\\xeaUY\\x95Y\\x93\\x96S\\x99S\\xa3d\\xd9UNUM\\x93V-cSUS5MU,\\xd6+SS3R\\xd3L\\xcc\\xcd2\\xd3-2\\xcc\\xcc\\xb3-+K+J\\xcc\\xb3*\\xd2\\xabR\\xaa\\xb5\\x1c\\xb2\\xca\\xad*\\xcb*\\xcb*\\xcb+*\\xcb+*\\xcb*\\xcc\\xaa\\xb4\\xac\\xab+,\\xca\\xabJ\\xcc\\xaa\\xd2\\xad+,\\xb2\\xcbJ\\xadK+3,\\xb5*\\xcd2\\xd2\\xcc\\xcc\\xb5J\\xb4\\xd4\\xb4\\xb3T\\xadM-M-S3T\\xb5R\\xd4\\xd5-U3T\\xce55M64\\xd5MScST\\xe3b\\xe3b\\xe4\\xd5USU\\x8bY64\\xe56656T\\xd5\\x8dS\\x93d\\xd59SX\\xd3\\x93Ub\\xd5UMU5UK\\x8dU.L\\xe35SMK\\x8d3T\\xcd3M4\\xcd-4\\xb3R\\xb3L\\xb4\\xad,\\xcb2\\xad2\\xac\\xb2\\xb3\\x1c\\xca\\xabF\\xca\\xb2r\\xac\\x9b*\\xaa\\xa9\\xcb\\x17)\\xb1\\xaarjk\\x19\\xa9\\xaa\\xa9\\\\\\x99\\xaai\\x9ai\\xa6\\x99\\x99\\xa9\\x96\\x99\\xa5je\\x99\\x96\\x99\\x95\\x9aV\\x99V\\x96fUjY:\\x95iU\\xa6UfeYfU\\xa4\\xea:N\\xa5Ve\\x95\\x99YfU\\xa5fVfU\\xa6U\\xa6Yfe\\x99iffe\\xa5\\xa6Zif\\x96\\xa6fjff\\xaaV\\xc5q\\xa6\\x9aj\\xa6j\\x9a\\xa9\\xa6\\xaa"

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■ 相关文献链接:

• WS2812串行可控彩色LED灯珠

● 相关图表链接:

• 图1.2.1 SPI管脚分布