kopia lustrzana https://github.com/eleccoder/raspi-pico-aprs-tnc
Split into lib + example application
rodzic
190667f82b
commit
906e390786
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@ -11,7 +11,7 @@ set(CMAKE_CXX_STANDARD 17)
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pico_sdk_init()
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# Setup of eleccoder's 'ax25-aprs-lib'
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# (1) Setup of eleccoder's 'ax25-aprs-lib'
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include(FetchContent)
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FetchContent_Declare(ax25_aprs_lib
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@ -24,30 +24,56 @@ FetchContent_MakeAvailable(ax25_aprs_lib)
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add_library(ax25_aprs_lib::ax25beacon ALIAS ax25beacon)
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# Setup of the application
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# (2) Configure the library build
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set(EXE_NAME aprs_pico)
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set(TARGET_LIB_NAME aprs_pico)
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add_executable(${EXE_NAME}
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src/aprs_pico.c
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add_library(${TARGET_LIB_NAME}
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src/aprs_pico.c)
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set_target_properties(${TARGET_LIB_NAME}
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PROPERTIES
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ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib"
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)
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target_include_directories(${EXE_NAME} PRIVATE
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target_include_directories(${TARGET_LIB_NAME} PUBLIC
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include
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)
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#target_compile_options(${EXE_NAME} PRIVATE "-Wall")
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# Enable on demand
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#target_compile_options(${TARGET_LIB_NAME} PRIVATE "-Wundef;-Wall")
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# Set the console interface
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pico_enable_stdio_usb(aprs_pico 1) # USB
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# pico_enable_stdio_uart(aprs_pico 1) # UART
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# create map/bin/hex file etc.
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pico_add_extra_outputs(${EXE_NAME})
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target_link_libraries(${EXE_NAME}
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pico_stdlib
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pico_audio_pwm
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# This properly resolves the include dirs of the dependent libraries
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target_link_libraries(${TARGET_LIB_NAME}
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ax25_aprs_lib::ax25beacon
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pico_audio_pwm
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pico_stdlib
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)
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# (3) Configure the example application build
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set(TARGET_EXAMPLE_EXE_NAME aprs_pico_example)
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add_executable(${TARGET_EXAMPLE_EXE_NAME}
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src/aprs_pico_example.c
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)
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target_include_directories(${TARGET_EXAMPLE_EXE_NAME} PRIVATE
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include
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)
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# Set the console interface
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pico_enable_stdio_usb(${TARGET_EXAMPLE_EXE_NAME} 1) # USB
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#pico_enable_stdio_uart(${TARGET_EXAMPLE_EXE_NAME} 1) # UART
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# create map/bin/hex file etc.
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pico_add_extra_outputs(${TARGET_EXAMPLE_EXE_NAME})
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target_link_libraries(${TARGET_EXAMPLE_EXE_NAME}
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${TARGET_LIB_NAME}
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ax25_aprs_lib::ax25beacon
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pico_audio_pwm
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pico_stdlib
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)
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23
README.md
23
README.md
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@ -6,21 +6,25 @@ An analog line-out audio signal will be produced at GPIO-pin 'GP0'. You can obse
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Basically, this is the data/signal flow:
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```
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APRS (text msg + geo-coordinates + meta-data) -> AX.25 -> PCM -> PWM -> Low-Pass filtering -> AFSK signal
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APRS (text msg + geo-coordinates + meta-data) -> AX.25 -> PCM -> PWM -> Band-Pass filtering -> AFSK audio signal
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```
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Both a static library `libaprs_pico.a` and an example application will be generated by the build.
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## Preliminaries
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Your host platform is assumed to be LINUX.
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If you have already installed the Pico-SDK, set the `PICO_SDK_PATH` environment variable accordingly to avoid installing the SDK twice.
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## Hardware
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We just need a simple band-pass filter to extract the AFSK-signal from the PWM signal:
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![band-pass filter](https://github.com/eleccoder/raspi-pico-aprs-tnc/blob/main/doc/schematic/band_pass_filter.png)
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## Build the application
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## Build the library and the example application
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```
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(cd into the cloned dir)
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@ -28,28 +32,27 @@ cmake -S . -B build
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cmake --build build
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```
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## Run the application
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`build/lib/libaprs_pico.a` and `build/aprs_pico_example.xxx` will be created.
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## Run the example application
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```
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cd build
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(flash 'aprs_pico.uf2' or 'aprs_pico.elf' to the Pico board as usual)
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(flash 'aprs_pico_example.uf2' or 'aprs_pico_example.elf' to the Pico board as usual)
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```
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The GPIO-pin 'GP0' is the line-out for the analog AFSK-signal. You can observe it by using a scope, listen to it by using an audio amp, or connect it to any RF transceiver to send it on the air (ham radio license required).
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![AFSK scope screenshot](https://github.com/eleccoder/raspi-pico-aprs-tnc/blob/main/doc/img/afsk_scope.png "Scope screenshot of an AFSK output signal")
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## Modify the application
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To send an APRS message of your choice, you have to modify the *main()* function in `src/aprs_pico.c`.
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## TODO (Aug 2021)
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- [x] Thorough evaluation
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- [x] Thorough evaluation, in general
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- [x] Send the APRS message on the console (USB or UART) rather than hard-coding
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- [x] Code documentation
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- [x] Show how to connect to a Baofeng HT
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- [x] PTT control for HTs
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- [x] PTT control for RF tranceivers
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## Acknowledgements
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@ -0,0 +1,44 @@
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/*
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* Project 'raspi-pico-aprs-tnc'
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* Copyright (C) 2021 Thomas Glau, DL3TG
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef APRS_PICO_H
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#define APRS_PICO_H
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#include <stdint.h>
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#include <stdbool.h>
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// WARNING: ATTOW, the pico audio PWM lib worked only @ 22050 Hz sampling frequency and 48 MHz system clock
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// This is documented here: https://github.com/raspberrypi/pico-extras
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#define APRS_PICO__PICO_EXTRA_AUDIO_PWM_LIB_FIXED_SAMPLE_FREQ_IN_HZ (22050)
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void sendAPRS(const char* call_sign_src,
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const char* call_sign_dst,
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const char* aprs_path_1,
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const char* aprs_path_2,
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const char* aprs_message,
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const double latitude_in_deg,
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const double longitude_in_deg,
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const double altitude_in_m,
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const uint8_t volume,
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const bool is_loop);
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void send1kHz(unsigned int sample_freq_in_hz, uint8_t volume);
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#endif // APRS_PICO_H
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@ -16,7 +16,8 @@
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdbool.h>
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#include <aprs_pico.h>
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#include <stdio.h>
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#include <math.h>
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@ -26,21 +27,16 @@
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#include <ax25beacon.h>
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// WARNING: ATTOW, the pico audio PWM lib worked only @ 22050 Hz sampling frequency and 48 MHz system clock
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// This is documented here: https://github.com/raspberrypi/pico-extras
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#define PICO_EXTRA_AUDIO_PWM_LIB_FIXED_SAMPLE_FREQ_IN_HZ (22050)
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#define SINE_WAVE_TEST (0) // For test & debug
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typedef struct AudioCallBackUserData
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{
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uint aprs_sample_freq_in_hz;
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unsigned int aprs_sample_freq_in_hz;
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bool is_loop;
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uint8_t volume;
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} AudioCallBackUserData_t;
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audio_buffer_pool_t* init_audio(uint sample_freq_in_hz, uint16_t audio_buffer_format)
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static audio_buffer_pool_t* init_audio(unsigned int sample_freq_in_hz, uint16_t audio_buffer_format)
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{
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const int NUM_AUDIO_BUFFERS = 3;
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const int SAMPLES_PER_BUFFER = 256;
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@ -68,12 +64,12 @@ audio_buffer_pool_t* init_audio(uint sample_freq_in_hz, uint16_t audio_buffer_fo
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}
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static void init(uint sample_freq_in_hz)
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static void init(unsigned int sample_freq_in_hz)
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{
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// WARNING: ATTOW, the pico audio PWM lib worked only @ 22050 Hz sampling frequency and 48 MHz system clock
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// This is documented here: https://github.com/raspberrypi/pico-extras
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if (sample_freq_in_hz == PICO_EXTRA_AUDIO_PWM_LIB_FIXED_SAMPLE_FREQ_IN_HZ)
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if (sample_freq_in_hz == APRS_PICO__PICO_EXTRA_AUDIO_PWM_LIB_FIXED_SAMPLE_FREQ_IN_HZ)
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{
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// This is the safe case, see the comment above
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set_sys_clock_48mhz();
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@ -83,7 +79,7 @@ static void init(uint sample_freq_in_hz)
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// Compensate a non-'PICO_EXTRA_AUDIO_PWM_LIB_FIXED_SAMPLE_FREQ_IN_HZ' sampling frequency
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// by a adapting the system clock accordingly
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float sys_clock_in_mhz = 48.0f * (float)sample_freq_in_hz / (float)PICO_EXTRA_AUDIO_PWM_LIB_FIXED_SAMPLE_FREQ_IN_HZ;
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float sys_clock_in_mhz = 48.0f * (float)sample_freq_in_hz / (float)APRS_PICO__PICO_EXTRA_AUDIO_PWM_LIB_FIXED_SAMPLE_FREQ_IN_HZ;
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// Round to full Mhz to increase the chance that 'set_sys_clock_khz()' can exactly realize this frequency
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sys_clock_in_mhz = round(sys_clock_in_mhz);
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@ -96,9 +92,9 @@ static void init(uint sample_freq_in_hz)
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static void fill_audio_buffer(audio_buffer_pool_t* audio_pool, const int16_t* pcm_data,
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uint num_samples, uint8_t volume, bool is_loop_forever)
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unsigned int num_samples, uint8_t volume, bool is_loop_forever)
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{
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uint pos = 0u;
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unsigned int pos = 0u;
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bool is_keep_going = true;
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while (is_keep_going)
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@ -106,7 +102,7 @@ static void fill_audio_buffer(audio_buffer_pool_t* audio_pool, const int16_t* pc
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audio_buffer_t* buffer = take_audio_buffer(audio_pool, true);
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int16_t* samples = (int16_t*)buffer->buffer->bytes;
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for (uint i = 0u; i < buffer->max_sample_count; i++)
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for (unsigned int i = 0u; i < buffer->max_sample_count; i++)
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{
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samples[i] = (volume * pcm_data[pos]) >> 8u;
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pos++;
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@ -131,13 +127,23 @@ static void fill_audio_buffer(audio_buffer_pool_t* audio_pool, const int16_t* pc
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}
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static void sendAPRS_audioCallback(void* callback_user_data, int16_t* pcm_data, size_t num_samples)
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{
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const AudioCallBackUserData_t user_data = *((const AudioCallBackUserData_t*)callback_user_data);
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audio_buffer_pool_t* audio_pool = init_audio(user_data.aprs_sample_freq_in_hz, AUDIO_BUFFER_FORMAT_PCM_S16);
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fill_audio_buffer(audio_pool, pcm_data, num_samples, user_data.volume, user_data.is_loop);
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}
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// Test tone: 1 kHz sine wave
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static void send1kHz(uint sample_freq_in_hz, uint8_t volume)
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void send1kHz( unsigned int sample_freq_in_hz, uint8_t volume)
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{
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init(sample_freq_in_hz);
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const uint tone_freq_in_hz = 1000u;
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const uint num_samples = sample_freq_in_hz / tone_freq_in_hz;
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const unsigned int TONE_FREQ_IN_HZ = 1000u;
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const unsigned int num_samples = sample_freq_in_hz / TONE_FREQ_IN_HZ;
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int16_t* sine_wave_table = malloc(num_samples * sizeof(int16_t));
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@ -146,7 +152,7 @@ static void send1kHz(uint sample_freq_in_hz, uint8_t volume)
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panic("Out of memory: malloc() failed.\n");
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}
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for (uint i = 0u; i < num_samples; i++)
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for (unsigned int i = 0u; i < num_samples; i++)
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{
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sine_wave_table[i] = (int16_t)(32767.0f * sinf(2.0f * (float)M_PI * (float)i / (float)num_samples));
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}
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@ -159,17 +165,7 @@ static void send1kHz(uint sample_freq_in_hz, uint8_t volume)
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}
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static void sendAPRS_audioCallback(void* callback_user_data, int16_t* pcm_data, size_t num_samples)
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{
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const AudioCallBackUserData_t user_data = *((const AudioCallBackUserData_t*)callback_user_data);
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audio_buffer_pool_t* audio_pool = init_audio(user_data.aprs_sample_freq_in_hz, AUDIO_BUFFER_FORMAT_PCM_S16);
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fill_audio_buffer(audio_pool, pcm_data, num_samples, user_data.volume, user_data.is_loop);
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}
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static void sendAPRS(const char* call_sign_src,
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void sendAPRS(const char* call_sign_src,
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const char* call_sign_dst,
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const char* aprs_path_1,
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const char* aprs_path_2,
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@ -200,30 +196,3 @@ static void sendAPRS(const char* call_sign_src,
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aprs_message,
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'/', 'O');
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}
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int main()
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{
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#if (SINE_WAVE_TEST == 1)
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const uint8_t VOLUME = 128u;
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send1kHz(PICO_EXTRA_AUDIO_PWM_LIB_FIXED_SAMPLE_FREQ_IN_HZ, VOLUME);
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#else // !SINE_WAVE_TEST
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// Send an APRS test message
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sendAPRS("SRC", // Src call sign
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"DST", // Dst call sign
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"PATH1",
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"PATH2",
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"Test message",
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10.0, // Lat in deg
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20.0, // Long in deg
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100.0, // Alt in m
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128u, // Volume (0 ... 255)
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false); // Loop forever
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#endif // SINE_WAVE_TEST, !SINE_WAVE_TEST
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return 0;
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}
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@ -0,0 +1,48 @@
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/*
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* Project 'raspi-pico-aprs-tnc'
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* Copyright (C) 2021 Thomas Glau, DL3TG
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*
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||||
* 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/>.
|
||||
*/
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#include <aprs_pico.h>
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#define SINE_WAVE_TEST (0) // For test & debug
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int main()
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{
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#if (SINE_WAVE_TEST == 1)
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const uint8_t VOLUME = 128u;
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send1kHz(APRS_PICO__PICO_EXTRA_AUDIO_PWM_LIB_FIXED_SAMPLE_FREQ_IN_HZ, VOLUME);
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#else // !SINE_WAVE_TEST
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// Send an APRS test message
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sendAPRS("SRC", // Src call sign
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"DST", // Dst call sign
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"PATH1",
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"PATH2",
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"Test message",
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10.0, // Lat in deg
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20.0, // Long in deg
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100.0, // Alt in m
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128u, // Volume (0 ... 255)
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false); // Loop forever
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#endif // SINE_WAVE_TEST, !SINE_WAVE_TEST
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return 0;
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}
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Ładowanie…
Reference in New Issue