kopia lustrzana https://github.com/markondej/fm_transmitter
57 wiersze
1.8 KiB
C++
57 wiersze
1.8 KiB
C++
#include "transmitter.h"
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#include <sys/mman.h>
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#include <fcntl.h>
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#include <exception>
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#include <iostream>
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#define ACCESS(base, offset) *(volatile unsigned int*)((int)base + offset)
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#define ACCESS64(base, offset) *(volatile unsigned long long*)((int)base + offset)
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Transmitter::Transmitter(double frequency)
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{
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int memFd;
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if ((memFd = open("/dev/mem", O_RDWR | O_SYNC)) < 0) {
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std::cout << "Error: sudo privileges are required" << std::endl;
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throw std::exception();
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}
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void *peripheralsMap = mmap(NULL, 0x002FFFFF, PROT_READ | PROT_WRITE, MAP_SHARED, memFd, 0x20000000);
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close(memFd);
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if (peripheralsMap == MAP_FAILED) {
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std::cout << "Error: cannot obtain access to peripherals (mmap error)" << std::endl;
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throw std::exception();
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}
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peripherals = (volatile unsigned*)peripheralsMap;
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ACCESS(peripherals, 0x00200000) = (ACCESS(peripherals, 0x00200000) & 0xFFFF8FFF) | (0x01 << 14);
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ACCESS(peripherals, 0x00101070) = (0x5A << 24) | (0x01 << 9) | (0x01 << 4) | 0x06;
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}
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void Transmitter::transmit(std::vector<unsigned int> *freqDivs, unsigned int sampleRate) {
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unsigned int offset = 0, length = freqDivs->size(), temp;
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unsigned int *data = &(*freqDivs)[0];
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unsigned long long current = 0;
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unsigned long long start = ACCESS64(peripherals, 0x00003004);
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while (true) {
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temp = offset;
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if (offset >= length) break;
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ACCESS(peripherals, 0x00101074) = (0x5A << 24) | data[offset];
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while (temp == offset) {
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usleep(1);
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current = ACCESS64(peripherals, 0x00003004);
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offset = (unsigned int)((current - start) * sampleRate / 1000000);
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}
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}
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}
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Transmitter::~Transmitter()
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{
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ACCESS(peripherals, 0x00101070) = (0x5A << 24);
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}
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