測試硅麥的輸出數據

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01 數字硅麥

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一、背景介紹

??手邊的這個數字硅麥，?是來自Infineon提供的樣品，?它的接口是PDM輸出。?在前面已經對該傳感器進行過初步的測試。?現在使用ESP32平臺來讀取該它的輸出信號。?根據測試，硅麥要求時鐘信號大于400kHz，?利用ESP32的SPI接口可以輸出超過這個頻率的時鐘信號，?同時可以讀入相應的數據。

二、ESP32輸入輸出

1、測試SPI脈沖

??根據 WS2812串行可控彩色LED燈珠 中的測試程序。?編寫SPI基本測試脈沖程序。?通過管腳14輸出時鐘信號，?時鐘頻率為2.5MHz。?這是測量ESP32第12管腳輸出波形，?可以看到對應的周期為400ns，頻率為2.5MHz。

from machine import Pin,Timer,SPI import timehspi = 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)

▲ 圖1.2.1 SPI管腳分布

??下面將SPI?輸出頻率修改成500KHz， ?輸入輸出2000個字節。?這是測量硅麥PDM輸出波形。?下面看看其中脈沖結構。?前面1ms是芯片啟動。?這部分是內部穩定時輸出信號?這里可以看到輸出帶有信號的波形。?

from machine import Pin,Timer,SPI import timehspi = 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)breakprint(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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■ 相關文獻鏈接:

• WS2812串行可控彩色LED燈珠

● 相關圖表鏈接:

• 圖1.2.1 SPI管腳分布

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