kopia lustrzana https://github.com/eleccoder/raspi-pico-aprs-tnc
229 wiersze
7.6 KiB
C
229 wiersze
7.6 KiB
C
/*
|
|
* Project 'raspi-pico-aprs-tnc'
|
|
* Copyright (C) 2021 Thomas Glau, DL3TG
|
|
*
|
|
* 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 3 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, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include <aprs_pico.h>
|
|
|
|
#include <stdio.h>
|
|
#include <math.h>
|
|
|
|
#include <pico/stdlib.h>
|
|
#include <pico/audio_pwm.h>
|
|
|
|
#include <ax25beacon.h>
|
|
|
|
|
|
typedef struct AudioCallBackUserData
|
|
{
|
|
unsigned int aprs_sample_freq_in_hz;
|
|
bool is_loop_forever;
|
|
uint8_t volume;
|
|
|
|
} AudioCallBackUserData_t;
|
|
|
|
|
|
/** \brief Init function for the Pico audio PWM library
|
|
*
|
|
* \param sample_freq_in_hz The sampling frequency to be used for audio signals
|
|
* \param audio_buffer_format The format of the audio buffers to be created, representing
|
|
* the data format of the audio samples
|
|
*
|
|
* \return A pool of audio buffers to be used for rendering an audio signal
|
|
*/
|
|
static audio_buffer_pool_t* init_audio(unsigned int sample_freq_in_hz, uint16_t audio_buffer_format)
|
|
{
|
|
const int NUM_AUDIO_BUFFERS = 3;
|
|
const int SAMPLES_PER_BUFFER = 256;
|
|
|
|
const audio_format_t audio_format = {.format = audio_buffer_format,
|
|
.sample_freq = sample_freq_in_hz,
|
|
.channel_count = 1};
|
|
|
|
audio_buffer_format_t producer_format = {.format = &audio_format,
|
|
.sample_stride = 2};
|
|
|
|
audio_buffer_pool_t* producer_pool = audio_new_producer_pool(&producer_format, NUM_AUDIO_BUFFERS, SAMPLES_PER_BUFFER);
|
|
|
|
if (!audio_pwm_setup(&audio_format, -1, &default_mono_channel_config))
|
|
{
|
|
panic("PicoAudio: Unable to open audio device.\n");
|
|
}
|
|
|
|
bool __unused is_ok = audio_pwm_default_connect(producer_pool, false);
|
|
assert(is_ok);
|
|
|
|
audio_pwm_set_enabled(true);
|
|
|
|
return producer_pool;
|
|
}
|
|
|
|
|
|
/** \brief Init function for the Pico's clock system and the Pico's standard library
|
|
*
|
|
* \param sample_freq_in_hz The sampling frequency to be used for rendering audio signals
|
|
*/
|
|
static void init_system(unsigned int sample_freq_in_hz)
|
|
{
|
|
// WARNING: ATTOW, the pico audio PWM lib worked only @ 22050 Hz sampling frequency and 48 MHz system clock
|
|
// This is documented here: https://github.com/raspberrypi/pico-extras
|
|
|
|
if (sample_freq_in_hz == APRS_PICO__PICO_EXTRA_AUDIO_PWM_LIB_FIXED_SAMPLE_FREQ_IN_HZ)
|
|
{
|
|
// This is the safe case, see the comment above
|
|
set_sys_clock_48mhz();
|
|
}
|
|
else
|
|
{
|
|
// Compensate a non-'PICO_EXTRA_AUDIO_PWM_LIB_FIXED_SAMPLE_FREQ_IN_HZ' sampling frequency
|
|
// by a adapting the system clock accordingly
|
|
|
|
const float SYS_CLOCK_FREQ_OF_PICO_EXTRA_AUDIO_PWM_LIB_IN_MHZ = 48.0f;
|
|
|
|
float sys_clock_in_mhz = SYS_CLOCK_FREQ_OF_PICO_EXTRA_AUDIO_PWM_LIB_IN_MHZ * (float)sample_freq_in_hz /
|
|
(float)APRS_PICO__PICO_EXTRA_AUDIO_PWM_LIB_FIXED_SAMPLE_FREQ_IN_HZ;
|
|
|
|
// Round to full Mhz to increase the chance that 'set_sys_clock_khz()' can exactly realize this frequency
|
|
sys_clock_in_mhz = round(sys_clock_in_mhz);
|
|
|
|
set_sys_clock_khz(1000u * (uint32_t)sys_clock_in_mhz, false);
|
|
}
|
|
|
|
stdio_init_all();
|
|
}
|
|
|
|
|
|
/** \brief Renders given PCM audio samples
|
|
*
|
|
* \param audio_pool The pool of audio buffers to be used for rendering an audio signal
|
|
* \param pcm_data The PCM audio samples to be rendered
|
|
* \param num_samples The number of samples to be rendered
|
|
* \param volume The volume level of the generated AFSK signal (0 ... 255)
|
|
* \param is_loop_forever If 'true', the rendering of the audio samples will be continuously repeated
|
|
*/
|
|
static void render_audio_samples(audio_buffer_pool_t* audio_pool, const int16_t* pcm_data,
|
|
unsigned int num_samples, uint8_t volume, bool is_loop_forever)
|
|
{
|
|
unsigned int pos = 0u;
|
|
bool is_keep_going = true;
|
|
|
|
while (is_keep_going)
|
|
{
|
|
audio_buffer_t* buffer = take_audio_buffer(audio_pool, true);
|
|
int16_t* samples = (int16_t*)buffer->buffer->bytes;
|
|
|
|
for (unsigned int i = 0u; i < buffer->max_sample_count; i++)
|
|
{
|
|
samples[i] = (volume * pcm_data[pos]) >> 8u;
|
|
pos++;
|
|
|
|
if (pos == num_samples)
|
|
{
|
|
if (is_loop_forever)
|
|
{
|
|
pos = 0u;
|
|
}
|
|
else
|
|
{
|
|
is_keep_going = false;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
buffer->sample_count = buffer->max_sample_count;
|
|
give_audio_buffer(audio_pool, buffer);
|
|
}
|
|
}
|
|
|
|
|
|
/** \brief The callback function to render the generated PCM audio samples of an APRS message
|
|
*
|
|
* \param callback_user_data User data provided by the caller function of this callback
|
|
* \param pcm_data The PCM audio samples to be rendered
|
|
* \param num_samples The number of samples the PCM data consist of
|
|
*/
|
|
static void sendAPRS_audioCallback(void* callback_user_data, int16_t* pcm_data, size_t num_samples)
|
|
{
|
|
const AudioCallBackUserData_t user_data = *((const AudioCallBackUserData_t*)callback_user_data);
|
|
|
|
audio_buffer_pool_t* audio_pool = init_audio(user_data.aprs_sample_freq_in_hz, AUDIO_BUFFER_FORMAT_PCM_S16);
|
|
|
|
render_audio_samples(audio_pool, pcm_data, num_samples, user_data.volume, user_data.is_loop_forever);
|
|
}
|
|
|
|
|
|
// See the header file for documentation
|
|
void send1kHz( unsigned int sample_freq_in_hz, uint8_t volume)
|
|
{
|
|
init_system(sample_freq_in_hz);
|
|
|
|
const unsigned int TONE_FREQ_IN_HZ = 1000u;
|
|
const unsigned int num_samples = sample_freq_in_hz / TONE_FREQ_IN_HZ;
|
|
|
|
int16_t* sine_wave_table = malloc(num_samples * sizeof(int16_t));
|
|
|
|
if (!sine_wave_table)
|
|
{
|
|
panic("Out of memory: malloc() failed.\n");
|
|
}
|
|
|
|
for (unsigned int i = 0u; i < num_samples; i++)
|
|
{
|
|
sine_wave_table[i] = (int16_t)(32767.0f * sinf(2.0f * (float)M_PI * (float)i / (float)num_samples));
|
|
}
|
|
|
|
audio_buffer_pool_t* audio_pool = init_audio(sample_freq_in_hz, AUDIO_BUFFER_FORMAT_PCM_S16);
|
|
|
|
render_audio_samples(audio_pool, sine_wave_table, num_samples, volume, true);
|
|
|
|
free(sine_wave_table);
|
|
}
|
|
|
|
|
|
// See the header file for documentation
|
|
void sendAPRS(const char* call_sign_src,
|
|
const char* call_sign_dst,
|
|
const char* aprs_path_1,
|
|
const char* aprs_path_2,
|
|
const char* aprs_message,
|
|
const double latitude_in_deg,
|
|
const double longitude_in_deg,
|
|
const double altitude_in_m,
|
|
const uint8_t volume,
|
|
const bool is_loop_forever)
|
|
{
|
|
static AudioCallBackUserData_t callback_user_data;
|
|
|
|
callback_user_data.aprs_sample_freq_in_hz = 48000u; // Known from the 'ax25beacon' library
|
|
callback_user_data.is_loop_forever = is_loop_forever;
|
|
callback_user_data.volume = volume;
|
|
|
|
init_system(callback_user_data.aprs_sample_freq_in_hz);
|
|
|
|
ax25_beacon((void*)&callback_user_data,
|
|
sendAPRS_audioCallback,
|
|
call_sign_src,
|
|
call_sign_dst,
|
|
aprs_path_1,
|
|
aprs_path_2,
|
|
latitude_in_deg,
|
|
longitude_in_deg,
|
|
altitude_in_m,
|
|
aprs_message,
|
|
'/', 'O');
|
|
}
|