Capelets/multiplexer-display/render.cpp

Display signals from the multiplexer capelet

This sketch displays the values of up to 64 analog inputs connected by the multiplexer capelet. The capelet is a separate piece of hardware that attaches to the Bela cape.

To run the sketch, the multiplexer capelet needs to be enabled using the IDE or with the -X command line option. The multiplexer capelet requires 8 analog inputs to work, and depending on the settings can use either 2, 4 or 8 multiplexer channels per analog input (for a total of 16, 32 or 64 inputs).

/*
 ____  _____ _        _
| __ )| ____| |      / \
|  _ \|  _| | |     / _ \
| |_) | |___| |___ / ___ \
|____/|_____|_____/_/   \_\
http://bela.io
*/
 
#include <Bela.h>
#include <unistd.h>
 
bool gIsStdoutTty;
unsigned int gPrintCount = 0;
 
bool setup(BelaContext *context, void *userData)
{
        if(context->multiplexerChannels == 0 || context->analogFrames == 0) {
                rt_printf("Please enable the Multiplexer Capelet to run this example.\n");
                return false;
        }
 
        gIsStdoutTty = isatty(1); // Check if stdout is a terminal
        return true;
}
 
void render(BelaContext *context, void *userData)
{
        gPrintCount += context->analogFrames;
 
        if(gPrintCount >= (unsigned int)(context->analogSampleRate * 0.1)) {
                gPrintCount = 0;
                if(gIsStdoutTty)
                        rt_printf("\e[1;1H\e[2J");      // Command to clear the screen (on a terminal)
 
                /* Go through each multiplexer setting of each analog input and display the value */
                for(unsigned int input = 0; input < context->analogInChannels; input++) {
                        rt_printf("Input %d: ", input);
                        for(unsigned int muxChannel = 0; muxChannel < context->multiplexerChannels; muxChannel++) {
                                /* multiplexerAnalogRead() returns the most recent sample from the given
                                 * input and mux channel. Unlike multiplexerChannelForFrame(), it does not
                                 * give you precise control over the frame timing, so this is mainly useful
                                 * for sensors where precise timing and sample rate is not as important.
                                 */
                                float sample = multiplexerAnalogRead(context, input, muxChannel);
                                rt_printf("%f ", sample);
                        }
                        rt_printf("\n");
                }
        }
}
 
void cleanup(BelaContext *context, void *userData)
{
 
}