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dvmfirmware-hs/dmr/DMRDMOTX.cpp

153 lines
4.0 KiB

// SPDX-License-Identifier: GPL-2.0-only
/*
* Digital Voice Modem - Hotspot Firmware
* GPLv2 Open Source. Use is subject to license terms.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* Copyright (C) 2009-2016 Jonathan Naylor, G4KLX
* Copyright (C) 2016 Colin Durbridge, G4EML
* Copyright (C) 2016,2017,2018 Andy Uribe, CA6JAU
* Copyright (C) 2021 Bryan Biedenkapp, N2PLL
*
*/
#include "Globals.h"
#include "dmr/DMRSlotType.h"
using namespace dmr;
// ---------------------------------------------------------------------------
// Constants
// ---------------------------------------------------------------------------
// PR FILL pattern
const uint8_t PR_FILL[] =
{ 0x63U, 0xEAU, 0x00U, 0x76U, 0x6CU, 0x76U, 0xC4U, 0x52U, 0xC8U, 0x78U,
0x09U, 0x2DU, 0xB8U, 0x79U, 0x27U, 0x57U, 0x9BU, 0x31U, 0xBCU, 0x3EU,
0xEAU, 0x45U, 0xC3U, 0x30U, 0x49U, 0x17U, 0x93U, 0xAEU, 0x8BU, 0x6DU,
0xA4U, 0xA5U, 0xADU, 0xA2U, 0xF1U, 0x35U, 0xB5U, 0x3CU, 0x1EU };
// ---------------------------------------------------------------------------
// Public Class Members
// ---------------------------------------------------------------------------
/* Initializes a new instance of the DMRDMOTX class. */
DMRDMOTX::DMRDMOTX() :
m_fifo(DMR_TX_BUFFER_LEN),
m_poBuffer(),
m_poLen(0U),
m_poPtr(0U),
m_preambleCnt(DMRDMO_FIXED_DELAY)
{
/* stub */
}
/* Process local buffer and transmit on the air interface. */
void DMRDMOTX::process()
{
if (m_poLen == 0U && m_fifo.getData() > 0U) {
if (!m_tx) {
for (uint16_t i = 0U; i < m_preambleCnt; i++)
m_poBuffer[i] = DMR_START_SYNC;
m_poLen = m_preambleCnt;
}
else {
for (unsigned int i = 0U; i < DMR_FRAME_LENGTH_BYTES; i++)
m_poBuffer[i] = m_fifo.get();
for (unsigned int i = 0U; i < 39U; i++)
m_poBuffer[i + DMR_FRAME_LENGTH_BYTES] = PR_FILL[i];
m_poLen = 72U;
}
m_poPtr = 0U;
}
if (m_poLen > 0U) {
uint16_t space = io.getSpace();
while (space > 8U) {
uint8_t c = m_poBuffer[m_poPtr++];
writeByte(c);
space -= 8U;
if (m_poPtr >= m_poLen) {
m_poPtr = 0U;
m_poLen = 0U;
return;
}
}
}
}
/* Write data to the local buffer. */
uint8_t DMRDMOTX::writeData(const uint8_t* data, uint8_t length)
{
if (length != (DMR_FRAME_LENGTH_BYTES + 1U))
return RSN_ILLEGAL_LENGTH;
uint16_t space = m_fifo.getSpace();
DEBUG3("DMRDMOTX::writeData() dataLength/fifoLength", length, space);
if (space < DMR_FRAME_LENGTH_BYTES)
return RSN_RINGBUFF_FULL;
for (uint8_t i = 0U; i < DMR_FRAME_LENGTH_BYTES; i++)
m_fifo.put(data[i + 1U]);
return RSN_OK;
}
/* Sets the FDMA preamble count. */
void DMRDMOTX::setPreambleCount(uint8_t preambleCnt)
{
uint32_t preambles = (uint32_t)((float)preambleCnt / 0.2083F);
m_preambleCnt = DMRDMO_FIXED_DELAY + preambles;
// clamp preamble count to 16ms maximum
if (m_preambleCnt > 80U)
m_preambleCnt = 80U;
}
/* Helper to resize the FIFO buffer. */
void DMRDMOTX::resizeBuffer(uint16_t size)
{
m_fifo.reset();
m_fifo.reinitialize(size);
}
/* Helper to get how much space the ring buffer has for samples. */
uint16_t DMRDMOTX::getSpace() const
{
return m_fifo.getSpace() / (DMR_FRAME_LENGTH_BYTES + 2U);
}
// ---------------------------------------------------------------------------
// Private Class Members
// ---------------------------------------------------------------------------
/* Helper to write a raw byte to the DAC. */
void DMRDMOTX::writeByte(uint8_t c)
{
uint8_t bit;
uint8_t mask = 0x80U;
for (uint8_t i = 0U; i < 8U; i++, c <<= 1) {
if ((c & mask) == mask)
bit = 1U;
else
bit = 0U;
io.write(&bit, 1);
}
}

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