A simple extension for reading Microchip MCP3008 A2D data via SPI in the Wolfram Language on the Raspberry Pi
by Joshua Schrier (2020) <jschrier [at] fordham [dot] edu>
(Tested on Raspbian 10 (buster) with Mathematica 12.0.1)
- wiring pi comes default in Raspbian (no installation necessary)
- Mathematica on the Raspberry Pi: the Makefile assumes version 12.0, but it is easy to change this.
- Be sure to enable SPI bus
A precompiled ARM-Linux binary for the Raspberry Pi (Raspian 10 on 3B+) is available in this repository. You can install it by running the following command in a terminal window:
curl https://github.com/jschrier/wl-mcp3008/blob/master/wl-mcp3008 --output ~/.Mathematica/Applications/wl-mcp3008
(This installs the package for the current user)
Note: The mcc compiler script provided for Mathematica 12 on Raspberry Pi has some defects associated with the -m32 and -m64 compiler flags. The simple solution is to comment those lines in mcc file. Open the file:
/opt/Wolfram/WolframEngine/12.0/SystemFiles/Links/MathLink/DeveloperKit/Linux-ARM/CompilerAdditions/mcc
(or whatever your version of the WolframEngine is) and then comment out these lines:
else # With gcc, target architecture is set by the -m32 and -m64 flags
if [ ${bitsize} = ${bit32} ] ; then
arch_flags="-m32"
elif [ ${bitsize} = ${bit64} ] && [ "${archi}" = "x86_64" ] ; then
arch_flags="-m64"
fi
Then just run:
make
make install
(default install path will put it into local user's .Mathematica/Applications/ directory, like above)
Minimum example (in Mathematica)
Install["wl-mcp3008"] (*loads the library*)
mcp3008[0] (* read from channel 0 *)
mcp3008[7] (*read from channel 7 *)
Returned values are integers; the MCP3008 returns 10 bit integers ranging from 0 to 1023.
Please note: This is hardwired to use the chip select channel 0 (CE0)