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set_ocoutputpwm.c

This is an example of how to use the OCOutput to let it generate PWM (pulse width modulation) signals.

#include <bluesense.h>

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>

bsOCOutputDevice_portEnum parsePort(char* s) {
        char side = s[0];
        uint8_t output = atoi(&s[1]);
  
        switch (side) {
                case 'A': {
                        switch (output) {
                                case 1: return bsOCOutput_pA_1;
                                case 2: return bsOCOutput_pA_2;
                                case 3: return bsOCOutput_pA_3;
                                case 4: return bsOCOutput_pA_4;
                                case 5: return bsOCOutput_pA_5;
                                case 6: return bsOCOutput_pA_6;
                                case 7: return bsOCOutput_pA_7;
                                case 8: return bsOCOutput_pA_8;
                        }
                }
                case 'B': {
                        switch (output) {
                                case 1: return bsOCOutput_pB_1;
                                case 2: return bsOCOutput_pB_2;
                                case 3: return bsOCOutput_pB_3;
                                case 4: return bsOCOutput_pB_4;
                                case 5: return bsOCOutput_pB_5;
                                case 6: return bsOCOutput_pB_6;
                                case 7: return bsOCOutput_pB_7;
                                case 8: return bsOCOutput_pB_8;
                        }
                }
        }
        return bsOCOutput_pA_1;
}



int main(int argc, char **argv) {
        char *progname = *argv++; argc--;

        // check argument count
        if(argc < 3) {
                fprintf(stderr, "\n");
                fprintf(stderr, 
                        "Please re-run this example with:\n");
                fprintf(stderr, 
                        "       identifier: identifier of the module\n");
                fprintf(stderr, 
                        "       port: output pin (A1..A6, B1..B6)\n");
                fprintf(stderr, 
                        "       value: pwmdutycycle (0..255)\n");
                fprintf(stderr, "\n");
                fprintf(stderr, 
                        "Usage: %s <identifier> <port> <pwm duty cycle 0..255>\n", progname);
                fprintf(stderr, 
                        "   eg: %s 10 A2 200\n", progname);
                fprintf(stderr, "\n");
                fprintf(stderr, 
                        "To find out what devices are connected try the 'list_devices' example.\n");
                fprintf(stderr, "\n");
                return(1);
        }

        // get identifier and from command line
        identifier_t id = atoi(argv[0]);

        // parses the port 
        bsOCOutputDevice_portEnum port = parsePort(argv[1]);
        // to be set duty cycle
        uint8_t dutycycle = atoi(argv[2]);
        
        // allocate memory for an interface table and resigster a known device interfaces
        bsDeviceInterface_registeredDeviceInterfaces_t registered = 
                bsDeviceInterface_allocInterfaceTable();
        
        // allocate memory of a device table and open a master device
        bsDeviceTable_table_t devices = bsDeviceTable_allocDeviceTable();
        bsMaster_device_t master = bsMaster_allocMaster(registered,devices,0);

        printf("Detecting device %d...\n", id);
        fflush(stdout);

        // try to find our device within the next 5 seconds
        bsDeviceTable_deviceInfo_t dev = 
                bsMaster_detectDevice(master, id, 5 * 1000 * 1000);

        // device not found?
        if(!dev) {
                fprintf(stderr, "Device %d not found!\n", id);

                // clean up previously allocated memory
                bsMaster_freeMaster(master);
                bsDeviceTable_freeDeviceTable(devices);
                bsDeviceInterface_freeInterfaceTable(registered);
                return(0);
        }

        if (bsDeviceTable_getDeviceFirmwareVersion(dev)<2) {
                fprintf(stderr, 
                        "PWM only supported on OCOutput module with firmware 2+!\n");

                // clean up previously allocated memory
                bsMaster_freeMaster(master);
                bsDeviceTable_freeDeviceTable(devices);
                bsDeviceInterface_freeInterfaceTable(registered);
                return(0);
        }

        // get specific device
        bsOCOutputDevice_specifics_t specDev = bsOCOutputDevice_getDeviceSpecifics(dev);
        
        fflush(stdout);

        uint8_t i = 0;
        uint32_t autoYieldParam =0;

        // wait for 200ms to retrieve initial states
        autoYieldParam = bsMaster_autoYield(master,200000,2000,autoYieldParam);

        bsOCOutputDevice_requestSetPWMDutyCycle(specDev,port,dutycycle);
        autoYieldParam = bsMaster_autoYield(master,200000,2000,autoYieldParam);

        printf("Device %d current outputs: %d\n", id,bsOCOutputDevice_getCurrentOutputs(specDev));
        for (i=0; i<16; i++) {
                printf("  PWM port %d has a duty cycle of %d\n",
                        i,
                        bsOCOutputDevice_getCurrentPWMDutyCycle(specDev,i));
        }

        // clean up previously allocated memory
        bsMaster_freeMaster(master);
        bsDeviceTable_freeDeviceTable(devices);
        bsDeviceInterface_freeInterfaceTable(registered);
        return(0);
}       


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