https://forge.codesys.com/forge/talk/Runtime/thread/3abf16c0cd/2020-02-27T16:06:51.090000ZRecent posts to Pi3 B+ with Stretch - MCP3008 SPI Not working2020-02-27T16:06:51.090000Z2020-02-27T16:06:51.090000Zeschwellingerhttps://forge.codesys.com/u/eschwellinger/https://forge.codesys.com5e9956d8afb7a68016d9d30f055a0d6d9d8060fc

<div class="markdown_content"><p>Hi,<br/> thanks for this helpful information for the community, well appreciated.</p> <p>BR<br/> Edwin</p></div>

2020-02-27T16:06:50.299000Z2020-02-27T16:06:50.299000ZAnerdgyhttps://forge.codesys.com/u/anerdgy/https://forge.codesys.com5cd4f40589ed207bdbdbccd33b0e2c6f651c4ac8

<div class="markdown_content"><p>Enable SPI1 on the raspberry pi in the config.txt</p> <p>Then add another device under the SPI and change the SPI port and MaxSpeed (due to stretch issue), move the MCP3008 into it.</p> <p>And all works. You can change the CS pin as well on the pi. </p> <p>I found this link useful . <a class="" href="https://terminal28.blogspot.com/2016/05/enabling-spi1-on-raspberry-pi-bzero23.html" rel="nofollow">https://terminal28.blogspot.com/2016/05/enabling-spi1-on-raspberry-pi-bzero23.html</a></p> <p><img alt="IMG: Capture2.PNG" rel="nofollow" src="https://forum.codesys.com//download/file.php?id=4110"/></p></div>

2020-02-27T16:06:48.077000Z2020-02-27T16:06:48.077000ZAnerdgyhttps://forge.codesys.com/u/anerdgy/https://forge.codesys.com9538798dba026c3c7bb33121aa876ac5eab86c83

<div class="markdown_content"><p>Through trial and error it seems that the max SPI clock speed is 7.8Mhz. If I go higher eg 15.6Mhz, I get a reduced scale and it no longer reads the values correctly.</p></div>

2020-02-27T16:06:47.283000Z2020-02-27T16:06:47.283000ZAnerdgyhttps://forge.codesys.com/u/anerdgy/https://forge.codesys.com3970dcbbba787d40cdfab89bb03a4725095d4a6b

<div class="markdown_content"><p>Many thanks. That solved it. I'm curious as to why the hardware code using the Adafruit python code worked as I had not changed the SPI speed.</p> <p>Secondly, how do I change it to use the second SPI hardware pins? ie using a differnet GPIO as chip select, BCM19 pin 35 MISO, BCM20 pin 38 MOSI and BCM21 pin 40 SCLK as I will now purchase a canberry dual board to mount and it is already using the original SPI pins as well as CE0 and CE1. Maybe I could just use a different GPIO for chip select , but if it affects the timing, maybe easier to move all the MCP3008 work onto the second SPI pins.</p> <p><a class="" href="https://www.industrialberry.com/canberrydual-iso-v2-1/" rel="nofollow">https://www.industrialberry.com/canberrydual-iso-v2-1/</a></p> <p>Many thanks</p> <p>Peter</p></div>

2020-02-27T16:06:46.392000Z2020-02-27T16:06:46.392000Zeschwellingerhttps://forge.codesys.com/u/eschwellinger/https://forge.codesys.com70b34d6ae336038c53a7d43b33832c088771c0db

<div class="markdown_content"><p>Hi,<br/> since Stretch fullspeed SPI does not work - so you need to reduce it here.<br/> BR<br/> Edwin</p> <p><img alt="IMG: SPIMaxSpeed.jpg" rel="nofollow" src="https://forum.codesys.com//download/file.php?id=4108"/></p></div>

2020-02-27T16:06:43.478000Z2020-02-27T16:06:43.478000ZAnerdgyhttps://forge.codesys.com/u/anerdgy/https://forge.codesys.coma1dec311e4f8d7a42cfe562b1d90223fc51defd8

<div class="markdown_content"><p>Hi</p> <p>am trying to get the MCP3008 to work with the Pi3 B+ using teh MCP3008 sample project.</p> <p>Unfortunately not receiving any readings. The hardware is defintely OK as with a python script I can read the values normally.</p> <p>I am using Hardware SPI.</p> <p>SPI master and devices running.</p> <p>Thanks in advance</p> <p>Peter</p> <p><img alt="IMG: Capture1.PNG" rel="nofollow" src="https://forum.codesys.com//download/file.php?id=4107"/></p></div>