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/* This program loads the two PRU programs into the PRU-ICSS transfers the configuration
* to the PRU memory spaces and starts the execution of both PRU programs.
* pressed. By Derek Molloy, for the book Exploring BeagleBone. Please see:
* for a full description of this code example and the associated programs.
#include <stdio.h>
#include <stdlib.h>
#include <prussdrv.h>
#include <pruss_intc_mapping.h>
#define ADC_PRU_NUM 0 // using PRU0 for the ADC capture
#define CLK_PRU_NUM 1 // using PRU1 for the sample clock
#define MMAP0_LOC "/sys/class/uio/uio0/maps/map0/"
#define MMAP1_LOC "/sys/class/uio/uio0/maps/map1/"
enum FREQUENCY { // measured and calibrated, but can be calculated
FREQ_12_5MHz = 1,
FREQ_6_25MHz = 5,
FREQ_5MHz = 7,
FREQ_3_85MHz = 10,
FREQ_1MHz = 45,
FREQ_500kHz = 95,
FREQ_250kHz = 245,
FREQ_100kHz = 495,
FREQ_25kHz = 1995,
FREQ_10kHz = 4995,
FREQ_5kHz = 9995,
FREQ_2kHz = 24995,
FREQ_1kHz = 49995
enum CONTROL {
// Short function to load a single unsigned int from a sysfs entry
unsigned int readFileValue(char filename[]){
FILE* fp;
unsigned int value = 0;
fp = fopen(filename, "rt");
fscanf(fp, "%x", &value);
return value;
int main (void)
printf("You must run this program as root. Exiting.\n");
// Initialize structure used by prussdrv_pruintc_intc
// PRUSS_INTC_INITDATA is found in pruss_intc_mapping.h
tpruss_intc_initdata pruss_intc_initdata = PRUSS_INTC_INITDATA;
// Read in the location and address of the shared memory. This value changes
// each time a new block of memory is allocated.
unsigned int timerData[2];
timerData[0] = FREQ_1MHz;
timerData[1] = RUNNING;
printf("The PRU clock state is set as period: %d (0x%x) and state: %d\n", timerData[0], timerData[0], timerData[1]);
unsigned int PRU_data_addr = readFileValue(MMAP0_LOC "addr");
printf("-> the PRUClock memory is mapped at the base address: %x\n", (PRU_data_addr + 0x2000));
printf("-> the PRUClock on/off state is mapped at address: %x\n", (PRU_data_addr + 0x10000));
// data for PRU0 based on the MCPXXXX datasheet
unsigned int spiData[3];
spiData[0] = 0x00000000;
spiData[1] = readFileValue(MMAP1_LOC "addr");
spiData[2] = readFileValue(MMAP1_LOC "size");
printf("Sending the SPI Control Data: 0x%x\n", spiData[0]);
printf("The DDR External Memory pool has location: 0x%x and size: 0x%x bytes\n", spiData[1], spiData[2]);
int numberSamples = spiData[2]/2;
printf("-> this space has capacity to store %d 16-bit samples (max)\n", numberSamples);
// Allocate and initialize memory
prussdrv_init ();
prussdrv_open (PRU_EVTOUT_0);
// Write the address and size into PRU0 Data RAM0. You can edit the value to
// PRUSS0_PRU1_DATARAM if you wish to write to PRU1
prussdrv_pru_write_memory(PRUSS0_PRU0_DATARAM, 0, spiData, 12); // spi code
prussdrv_pru_write_memory(PRUSS0_PRU1_DATARAM, 0, timerData, 8); // sample clock
// Map the PRU's interrupts
// Load and execute the PRU program on the PRU
prussdrv_exec_program (ADC_PRU_NUM, "./PRUADC.bin");
prussdrv_exec_program (CLK_PRU_NUM, "./PRUClock.bin");
printf("EBBClock PRU1 program now running (%d)\n", timerData[0]);
// Wait for event completion from PRU, returns the PRU_EVTOUT_0 number
int n = prussdrv_pru_wait_event (PRU_EVTOUT_0);
printf("EBBADC PRU0 program completed, event number %d.\n", n);
// Disable PRU and close memory mappings
prussdrv_exit ();