mirror of
https://github.com/g4klx/MMDVM.git
synced 2026-10-22 18:45:01 +02:00
Initial P25 test support.
This commit is contained in:
Jonathan Naylor
@@ -0,0 +1,281 @@
|
||||
/*
|
||||
* Copyright (C) 2016 by Jonathan Naylor G4KLX
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation; either version 2 of the License, or
|
||||
* (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
||||
*/
|
||||
|
||||
#define WANT_DEBUG
|
||||
|
||||
#include "Config.h"
|
||||
#include "Globals.h"
|
||||
#include "P25RX.h"
|
||||
#include "Utils.h"
|
||||
|
||||
const unsigned int BUFFER_LENGTH = 200U;
|
||||
|
||||
const q15_t SCALING_FACTOR = 18750; // Q15(0.55)
|
||||
|
||||
const uint32_t PLLMAX = 0x10000U;
|
||||
const uint32_t PLLINC = PLLMAX / P25_RADIO_SYMBOL_LENGTH;
|
||||
const uint32_t INC = PLLINC / 32U;
|
||||
|
||||
const uint8_t SYNC_SYMBOL_ERRS = 0U;
|
||||
|
||||
const uint8_t SYNC_BIT_START_ERRS = 2U;
|
||||
const uint8_t SYNC_BIT_RUN_ERRS = 4U;
|
||||
|
||||
const unsigned int MAX_SYNC_FRAMES = 4U + 1U;
|
||||
|
||||
const uint8_t BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U};
|
||||
|
||||
#define WRITE_BIT1(p,i,b) p[(i)>>3] = (b) ? (p[(i)>>3] | BIT_MASK_TABLE[(i)&7]) : (p[(i)>>3] & ~BIT_MASK_TABLE[(i)&7])
|
||||
#define READ_BIT1(p,i) (p[(i)>>3] & BIT_MASK_TABLE[(i)&7])
|
||||
|
||||
CP25RX::CP25RX() :
|
||||
m_pll(0U),
|
||||
m_prev(false),
|
||||
m_state(P25RXS_NONE),
|
||||
m_bitBuffer(0x00U),
|
||||
m_symbols(),
|
||||
m_outBuffer(),
|
||||
m_buffer(NULL),
|
||||
m_bufferPtr(0U),
|
||||
m_symbolPtr(0U),
|
||||
m_lostCount(0U),
|
||||
m_rssiCount(0U),
|
||||
m_centre(0),
|
||||
m_threshold(0)
|
||||
{
|
||||
m_buffer = m_outBuffer + 1U;
|
||||
}
|
||||
|
||||
void CP25RX::reset()
|
||||
{
|
||||
m_pll = 0U;
|
||||
m_prev = false;
|
||||
m_state = P25RXS_NONE;
|
||||
m_bitBuffer = 0x00U;
|
||||
m_bufferPtr = 0U;
|
||||
m_symbolPtr = 0U;
|
||||
m_lostCount = 0U;
|
||||
m_rssiCount = 0U;
|
||||
m_centre = 0;
|
||||
m_threshold = 0;
|
||||
}
|
||||
|
||||
void CP25RX::samples(const q15_t* samples, uint8_t length)
|
||||
{
|
||||
for (uint16_t i = 0U; i < length; i++) {
|
||||
bool bit = samples[i] < 0;
|
||||
|
||||
if (bit != m_prev) {
|
||||
if (m_pll < (PLLMAX / 2U))
|
||||
m_pll += INC;
|
||||
else
|
||||
m_pll -= INC;
|
||||
}
|
||||
|
||||
m_prev = bit;
|
||||
|
||||
m_pll += PLLINC;
|
||||
|
||||
if (m_pll >= PLLMAX) {
|
||||
m_pll -= PLLMAX;
|
||||
|
||||
if (m_state == P25RXS_NONE)
|
||||
processNone(samples[i]);
|
||||
else
|
||||
processData(samples[i]);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
void CP25RX::processNone(q15_t sample)
|
||||
{
|
||||
m_symbolBuffer <<= 1;
|
||||
if (sample < 0)
|
||||
m_symbolBuffer |= 0x01U;
|
||||
|
||||
m_symbols[m_symbolPtr] = sample;
|
||||
|
||||
// Fuzzy matching of the data sync bit sequence
|
||||
if (countBits32((m_symbolBuffer & P25_SYNC_SYMBOLS_MASK) ^ P25_SYNC_SYMBOLS) <= SYNC_SYMBOL_ERRS) {
|
||||
q15_t max = -16000;
|
||||
q15_t min = 16000;
|
||||
|
||||
for (uint8_t i = 0U; i < P25_SYNC_LENGTH_SYMBOLS; i++) {
|
||||
q15_t val = m_symbols[i];
|
||||
if (val > max)
|
||||
max = val;
|
||||
if (val < min)
|
||||
min = val;
|
||||
}
|
||||
|
||||
q15_t centre = (max + min) >> 1;
|
||||
|
||||
q31_t v1 = (max - centre) * SCALING_FACTOR;
|
||||
q15_t threshold = q15_t(v1 >> 15);
|
||||
|
||||
uint16_t ptr = m_symbolPtr + 1U;
|
||||
if (ptr >= P25_SYNC_LENGTH_SYMBOLS)
|
||||
ptr = 0U;
|
||||
|
||||
for (uint8_t i = 0U; i < P25_SYNC_LENGTH_SYMBOLS; i++) {
|
||||
q15_t sample = m_symbols[ptr] - centre;
|
||||
|
||||
if (sample < -threshold) {
|
||||
m_bitBuffer <<= 2;
|
||||
m_bitBuffer |= 0x01U;
|
||||
} else if (sample < 0) {
|
||||
m_bitBuffer <<= 2;
|
||||
m_bitBuffer |= 0x00U;
|
||||
} else if (sample < threshold) {
|
||||
m_bitBuffer <<= 2;
|
||||
m_bitBuffer |= 0x02U;
|
||||
} else {
|
||||
m_bitBuffer <<= 2;
|
||||
m_bitBuffer |= 0x03U;
|
||||
}
|
||||
|
||||
ptr++;
|
||||
if (ptr >= P25_SYNC_LENGTH_SYMBOLS)
|
||||
ptr = 0U;
|
||||
}
|
||||
|
||||
// Fuzzy matching of the data sync bit sequence
|
||||
if (countBits64((m_bitBuffer & P25_SYNC_BITS_MASK) ^ P25_SYNC_BITS) <= SYNC_BIT_START_ERRS) {
|
||||
DEBUG5("P25RX: sync found in None min/max/centre/threshold", min, max, centre, threshold);
|
||||
for (uint8_t i = 0U; i < P25_SYNC_LENGTH_BYTES; i++)
|
||||
m_buffer[i] = P25_SYNC_BYTES[i];
|
||||
m_centre = centre;
|
||||
m_threshold = threshold;
|
||||
m_lostCount = MAX_SYNC_FRAMES;
|
||||
m_bufferPtr = P25_SYNC_LENGTH_BITS;
|
||||
m_state = P25RXS_DATA;
|
||||
m_rssiCount = 0U;
|
||||
|
||||
io.setDecode(true);
|
||||
io.setADCDetection(true);
|
||||
}
|
||||
}
|
||||
|
||||
m_symbolPtr++;
|
||||
if (m_symbolPtr >= P25_SYNC_LENGTH_SYMBOLS)
|
||||
m_symbolPtr = 0U;
|
||||
}
|
||||
|
||||
void CP25RX::processData(q15_t sample)
|
||||
{
|
||||
sample -= m_centre;
|
||||
|
||||
if (sample < -m_threshold) {
|
||||
m_bitBuffer <<= 2;
|
||||
m_bitBuffer |= 0x01U;
|
||||
WRITE_BIT1(m_buffer, m_bufferPtr, false);
|
||||
m_bufferPtr++;
|
||||
WRITE_BIT1(m_buffer, m_bufferPtr, true);
|
||||
m_bufferPtr++;
|
||||
} else if (sample < 0) {
|
||||
m_bitBuffer <<= 2;
|
||||
m_bitBuffer |= 0x00U;
|
||||
WRITE_BIT1(m_buffer, m_bufferPtr, false);
|
||||
m_bufferPtr++;
|
||||
WRITE_BIT1(m_buffer, m_bufferPtr, false);
|
||||
m_bufferPtr++;
|
||||
} else if (sample < m_threshold) {
|
||||
m_bitBuffer <<= 2;
|
||||
m_bitBuffer |= 0x02U;
|
||||
WRITE_BIT1(m_buffer, m_bufferPtr, true);
|
||||
m_bufferPtr++;
|
||||
WRITE_BIT1(m_buffer, m_bufferPtr, false);
|
||||
m_bufferPtr++;
|
||||
} else {
|
||||
m_bitBuffer <<= 2;
|
||||
m_bitBuffer |= 0x03U;
|
||||
WRITE_BIT1(m_buffer, m_bufferPtr, true);
|
||||
m_bufferPtr++;
|
||||
WRITE_BIT1(m_buffer, m_bufferPtr, true);
|
||||
m_bufferPtr++;
|
||||
}
|
||||
|
||||
// Search for an early sync to indicate an LDU following a header
|
||||
if (m_bufferPtr >= (P25_HDR_FRAME_LENGTH_BITS + P25_SYNC_LENGTH_BITS - 2U) && m_bufferPtr <= (P25_HDR_FRAME_LENGTH_BITS + P25_SYNC_LENGTH_BITS + 2U)) {
|
||||
// Fuzzy matching of the data sync bit sequence
|
||||
if (countBits64((m_bitBuffer & P25_SYNC_BITS_MASK) ^ P25_SYNC_BITS) <= SYNC_BIT_RUN_ERRS) {
|
||||
DEBUG2("P25RX: found LDU sync in Data, pos", m_bufferPtr - P25_SYNC_LENGTH_BITS);
|
||||
|
||||
m_outBuffer[0U] = 0x00U;
|
||||
serial.writeP25Hdr(m_outBuffer, P25_HDR_FRAME_LENGTH_BYTES + 1U);
|
||||
|
||||
// Restore the sync that's now in the wrong place
|
||||
for (uint8_t i = 0U; i < P25_SYNC_LENGTH_BYTES; i++)
|
||||
m_buffer[i] = P25_SYNC_BYTES[i];
|
||||
|
||||
m_lostCount = MAX_SYNC_FRAMES;
|
||||
m_bufferPtr = P25_SYNC_LENGTH_BITS;
|
||||
}
|
||||
}
|
||||
|
||||
// Only search for a sync in the right place +-2 symbols
|
||||
if (m_bufferPtr >= (P25_SYNC_LENGTH_BITS - 2U) && m_bufferPtr <= (P25_SYNC_LENGTH_BITS + 2U)) {
|
||||
// Fuzzy matching of the data sync bit sequence
|
||||
if (countBits64((m_bitBuffer & P25_SYNC_BITS_MASK) ^ P25_SYNC_BITS) <= SYNC_BIT_RUN_ERRS) {
|
||||
DEBUG2("P25RX: found sync in Data, pos", m_bufferPtr - P25_SYNC_LENGTH_BITS);
|
||||
m_lostCount = MAX_SYNC_FRAMES;
|
||||
m_bufferPtr = P25_SYNC_LENGTH_BITS;
|
||||
}
|
||||
}
|
||||
|
||||
// Send a data frame to the host if the required number of bits have been received
|
||||
if (m_bufferPtr == P25_LDU_FRAME_LENGTH_BITS) {
|
||||
// We've not seen a data sync for too long, signal RXLOST and change to RX_NONE
|
||||
m_lostCount--;
|
||||
if (m_lostCount == 0U) {
|
||||
DEBUG1("P25RX: sync timed out, lost lock");
|
||||
|
||||
io.setDecode(false);
|
||||
io.setADCDetection(false);
|
||||
|
||||
serial.writeP25Lost();
|
||||
|
||||
m_state = P25RXS_NONE;
|
||||
} else {
|
||||
m_outBuffer[0U] = m_lostCount == (MAX_SYNC_FRAMES - 1U) ? 0x01U : 0x00U;
|
||||
|
||||
#if defined(SEND_RSSI_DATA)
|
||||
// Send RSSI data every second
|
||||
if (m_rssiCount == 0U) {
|
||||
uint16_t rssi = io.getRSSIValue();
|
||||
m_outBuffer[121U] = (rssi >> 8) & 0xFFU;
|
||||
m_outBuffer[122U] = (rssi >> 0) & 0xFFU;
|
||||
serial.writeP25Ldu(m_outBuffer, P25_LDU_FRAME_LENGTH_BYTES + 3U);
|
||||
} else {
|
||||
serial.writeP25Ldu(m_outBuffer, P25_LDU_FRAME_LENGTH_BYTES + 1U);
|
||||
}
|
||||
|
||||
m_rssiCount++;
|
||||
if (m_rssiCount >= 10U)
|
||||
m_rssiCount = 0U;
|
||||
#else
|
||||
serial.writeP25Ldu(m_outBuffer, P25_LDU_FRAME_LENGTH_BYTES + 1U);
|
||||
#endif
|
||||
|
||||
// Start the next frame
|
||||
::memset(m_outBuffer, 0x00U, P25_LDU_FRAME_LENGTH_BYTES + 3U);
|
||||
m_bufferPtr = 0U;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user