Waveshare AD/DA Expansion Board

Question

So today I recieved a Waveform High Precision AD/DA Expansion Board for me to use with my Pi3. Prior I was using an MCP3008 ADC chip to measure voltages, and I just wanted to see if I could get better readings off of this since the AD chip on the board is 24 bit as opposed to the MCP3008's 10 bit read value.

However I did not realize how new the board is and because of that there is basically very little info online on how to go about setting some of this up properly. I know it just plugs into the Pi, but specifically I am curious about how i'd go about wiring it in a way similar to what I was doing with the MCP3008 chip. If anyone has any experience using the board I'd appreciate some help :)

Answer 1

Given this board plugs into the Pi's GPIO pins you should only have to connect your analog source to the board, and configure the jumpers.

From the images on the linked page, it would appear the simplest method is to use the green screw terminals at the top of the board (opposite the GPIO header), they are labeled A00-A07.

It also looks like you could use female jumper wires and the male headers on the left of the board. The third column labeled A would be the analog connections.

The waveshare wiki has some decent documentation for this board. Including the required jumper settings and testing info.

Answer 2

I set up this board recently and it was a bit of a struggle. Here's what worked for me:

setup

1) Wire all of the pins on the front "bank" (opposite from the green screw pins) of the board to their corresponding pins on the Pi. There is also a jumper between AINCOM and AGND which may be left on (this is on my board; if there's no jumper, add that connection). Also add a connection from

2) Wire 5V to VCC and 5V to VREF on the right hand yellow bank of pins. Mine came with jumpers in, connecting 5V to 3.3V on both sides. Just shift them forward one and you're good to go.

3) Wire LEDB to DAC1 and LEDA to DAC0. Again, jumpers, so not necessary.

4) If you have jumpers in the right bank, remove the two jumpers connecting AD1 to LDR and AD0 to ADJ.

5) Download the code from here, unzip (you can get a free trial of winzip, which works nicely), and transfer to the pi using a jump drive. Once on the pi move it off the jump drive. I just moved it into the ~/Documents directory.

6) Use the code given here in the command line of your pi to install bcm2835.

7) cd into the folder that has the code downloaded in step 5 and cd into the DAC8532 folder. Type in make, then sudo ./dac832_test. If this doesn't work, run chmod +x dac8532_test then the above. If that doesn't work, add sudo to your call to chmod. If that doesn't work, look at some of the solutions here in the comments.

At this point, the LEDs on the board should blink (item 7 was to run a test file) and your board is properly setup.

python use

1) install required packages - do sudo apt-get update then sudo apt-get install python-dev. On my Pi this was automatically installed. Other packages to install:

• sudo apt-get install python-rpi.gpio
• sudo apt-get install python-smbus
• sudo apt-get install python-serial
• sudo apt-get install python-spidev
• sudo apt-get install python-imaging

2) turn I2C, SPI, and serial on. Do this by doing sudo raspi-config then going to #5 - interfacing options, then selecting P4 (SPI), P5 (I2C), and P6 (serial) and following the prompts given to turn them each on.

3)

I'll add to this as I figure out more (hopefully with stuff on using with Python and on wiring up to various output pins of the Pi), but this was hard for me to figure out for the reasons you provide, along with the fact that I'm a newbie when it comes to this stuff, so I thought I'd write it up here. I apologize though because I don't know about the MCP3008 chip and I'm exactly a year late. Relevant xkcd.