Output I2S audio with PIO/DMA
Requires a MAX98357A amplifier and a 2W 8ohms speaker
This commit is contained in:
Vincent Mistler
+13
-13
@@ -1,24 +1,24 @@
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cmake_minimum_required(VERSION 3.13...3.23)
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# initialize the SDK based on PICO_SDK_PATH
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include(pico_sdk_import.cmake)
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project(RP2040_GB C CXX)
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project(RP2040_GB C CXX ASM)
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set(CMAKE_C_STANDARD 11)
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set(CMAKE_CXX_STANDARD 17)
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# Initialize the Raspberry Pi Pico SDK
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pico_sdk_init()
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add_executable(RP2040_GB src/main.c src/rom.c src/mk_ili9225.c)
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target_include_directories(RP2040_GB PRIVATE inc)
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add_executable(RP2040_GB
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src/main.c
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src/rom.c
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src/mk_ili9225.c
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ext/minigb_apu/minigb_apu.c
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ext/i2s/i2s.c
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)
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SET(ENABLE_SOUND FALSE CACHE BOOL "Enable Sound emulation")
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if(ENABLE_SOUND)
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ADD_COMPILE_DEFINITIONS(ENABLE_SOUND=1)
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target_sources(RP2040_GB PRIVATE ext/minigb_apu/minigb_apu.c)
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target_include_directories(RP2040_GB PRIVATE ext/minigb_apu)
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else()
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ADD_COMPILE_DEFINITIONS(ENABLE_SOUND=0)
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endif()
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pico_generate_pio_header(RP2040_GB ${CMAKE_CURRENT_LIST_DIR}/ext/i2s/audio_i2s.pio)
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target_include_directories(RP2040_GB PRIVATE inc ext/minigb_apu ext/i2s)
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target_link_libraries(RP2040_GB
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pico_stdlib pico_stdio pico_bootrom pico_multicore pico_stdio pico_multicore
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@@ -7,6 +7,16 @@ This fork includes all changes needed for the emulator to run on the [Pico-GB em
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RP2040-GB is a Game Boy (DMG) emulator [Peanut-GB](https://github.com/deltabeard/Peanut-GB) on the Raspberry Pi RP2040 microcontroller, using an ILI9225 screen.
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Runs at more than 70 fps without audio emulation. With frame skip and interlacing, can run at up to 120 fps.
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# What you need
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* Raspberry Pi Pico (1x)
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* 2.2inch ILI9225 176×220 LCD Display Module (1x)
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* MAX98357A amplifier (1x)
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* 2W 8ohms speaker (1x)
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* Micro Push Button Switch, Momentary Tactile Tact Touch, 6x6x6 mm, 4 pins (8x)
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* Solderable Breadboard (1x)
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* Dupont Wires Assorted Kit (Male to Female + Male to Male + Female to Female)
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* Preformed Breadboard Jumper Wires
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# Raspberry Pi Pico Pins Assignment
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* UP = GP2
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* DOWN = GP3
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@@ -16,13 +26,15 @@ Runs at more than 70 fps without audio emulation. With frame skip and interlacin
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* BUTTON B = GP7
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* SELECT = GP8
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* START = GP9
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* BUZZER = GP15
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* LCD CS = GP17
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* LCD CLK = GP18
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* LCD SDI = GP19
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* LCD RS = GP20
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* LCD RST = GP21
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* LCD LED = GP22
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* MAX98357A DIN = GP26
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* MAX98357A BCLK = GP27
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* MAX98357A LRC = GP28
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# Installing
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@@ -0,0 +1,63 @@
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;
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; Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
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;
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; SPDX-License-Identifier: BSD-3-Clause
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;
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; Transmit a mono or stereo I2S audio stream as stereo
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; This is 16 bits per sample; can be altered by modifying the "set" params,
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; or made programmable by replacing "set x" with "mov x, y" and using Y as a config register.
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;
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; Autopull must be enabled, with threshold set to 32.
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; Since I2S is MSB-first, shift direction should be to left.
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; Hence the format of the FIFO word is:
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;
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; | 31 : 16 | 15 : 0 |
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; | sample ws=0 | sample ws=1 |
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;
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; Data is output at 1 bit per clock. Use clock divider to adjust frequency.
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; Fractional divider will probably be needed to get correct bit clock period,
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; but for common syslck freqs this should still give a constant word select period.
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;
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; One output pin is used for the data output.
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; Two side-set pins are used. Bit 0 is clock, bit 1 is word select.
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; Send 16 bit words to the PIO for mono, 32 bit words for stereo
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.program audio_i2s
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.side_set 2
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; /--- LRCLK
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; |/-- BCLK
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bitloop1: ; ||
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out pins, 1 side 0b10
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jmp x-- bitloop1 side 0b11
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out pins, 1 side 0b00
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set x, 14 side 0b01
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bitloop0:
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out pins, 1 side 0b00
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jmp x-- bitloop0 side 0b01
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out pins, 1 side 0b10
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public entry_point:
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set x, 14 side 0b11
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% c-sdk {
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static inline void audio_i2s_program_init(PIO pio, uint sm, uint offset, uint data_pin, uint clock_pin_base) {
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pio_sm_config sm_config = audio_i2s_program_get_default_config(offset);
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sm_config_set_out_pins(&sm_config, data_pin, 1);
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sm_config_set_sideset_pins(&sm_config, clock_pin_base);
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sm_config_set_out_shift(&sm_config, false, true, 32);
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pio_sm_init(pio, sm, offset, &sm_config);
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uint pin_mask = (1u << data_pin) | (3u << clock_pin_base);
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pio_sm_set_pindirs_with_mask(pio, sm, pin_mask, pin_mask);
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pio_sm_set_pins(pio, sm, 0); // clear pins
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pio_sm_exec(pio, sm, pio_encode_jmp(offset + audio_i2s_offset_entry_point));
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}
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%}
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+100
@@ -0,0 +1,100 @@
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/**
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* MIT License
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*
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* Copyright (c) 2022 Vincent Mistler
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include "i2s.h"
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i2s_config_t i2s_get_default_config(void) {
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i2s_config_t i2s_config = {
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.sample_freq = 44100,
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.channel_count = 2,
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.data_pin = 26,
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.clock_pin_base = 27,
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.pio = pio0,
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.sm = 0,
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.dma_channel = 0,
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.dma_buf = NULL,
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.dma_trans_count = 0,
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};
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return i2s_config;
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}
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void i2s_init(i2s_config_t *i2s_config) {
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uint8_t func=GPIO_FUNC_PIO0; // TODO: GPIO_FUNC_PIO0 for pio0 or GPIO_FUNC_PIO1 for pio1
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gpio_set_function(i2s_config->data_pin, GPIO_FUNC_PIO0);
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gpio_set_function(i2s_config->clock_pin_base, GPIO_FUNC_PIO0);
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gpio_set_function(i2s_config->clock_pin_base+1, GPIO_FUNC_PIO0);
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i2s_config->sm = pio_claim_unused_sm(i2s_config->pio, true);
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uint offset = pio_add_program(i2s_config->pio, &audio_i2s_program);
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audio_i2s_program_init(i2s_config->pio, i2s_config->sm , offset, i2s_config->data_pin , i2s_config->clock_pin_base);
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// Set PIO clock
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uint32_t system_clock_frequency = clock_get_hz(clk_sys);
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uint32_t divider = system_clock_frequency * 4 / i2s_config->sample_freq; // avoid arithmetic overflow
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pio_sm_set_clkdiv_int_frac(i2s_config->pio, i2s_config->sm , divider >> 8u, divider & 0xffu);
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pio_sm_set_enabled(i2s_config->pio, i2s_config->sm, false);
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// Allocate memory for the DMA buffer
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i2s_config->dma_buf=malloc(i2s_config->dma_trans_count*sizeof(uint32_t));
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// Direct Memory Access setup
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i2s_config->dma_channel = dma_claim_unused_channel(true);
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dma_channel_config dma_config = dma_channel_get_default_config(i2s_config->dma_channel);
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channel_config_set_read_increment(&dma_config, true);
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channel_config_set_write_increment(&dma_config, false);
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channel_config_set_dreq(&dma_config, pio_get_dreq(i2s_config->pio, i2s_config->sm, true));
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channel_config_set_transfer_data_size(&dma_config, DMA_SIZE_32);
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dma_channel_configure(i2s_config->dma_channel,
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&dma_config,
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&(i2s_config->pio->txf[i2s_config->sm]), // Destination pointer
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i2s_config->dma_buf, // Source pointer
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i2s_config->dma_trans_count, // Number of 32 bits words to transfer
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false // Start immediately
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);
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pio_sm_set_enabled(i2s_config->pio, i2s_config->sm , true);
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}
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void i2s_write(const i2s_config_t *i2s_config,const int16_t *samples,const size_t len) {
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for(size_t i=0;i<len;i++) {
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pio_sm_put_blocking(i2s_config->pio, i2s_config->sm, (uint32_t)samples[i]);
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}
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}
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// Write samples to DMA buffer and initiate DMA transfer (non blocking)
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void i2s_dma_write(i2s_config_t *i2s_config,const int16_t *samples) {
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// Wait the completion of the previous DMA transfer
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dma_channel_wait_for_finish_blocking(i2s_config->dma_channel);
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// Copy samples into the DMA buffer
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memcpy(i2s_config->dma_buf,samples,i2s_config->dma_trans_count*sizeof(int32_t));
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// Initiate the DMA transfer
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dma_channel_transfer_from_buffer_now(i2s_config->dma_channel,
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i2s_config->dma_buf,
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i2s_config->dma_trans_count);
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}
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@@ -0,0 +1,52 @@
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/**
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* MIT License
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*
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* Copyright (c) 2022 Vincent Mistler
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
|
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
|
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* sell copies of the Software, and to permit persons to whom the Software is
|
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
|
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#pragma once
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#include <stdlib.h>
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#include <string.h>
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#include <hardware/pio.h>
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#include <hardware/clocks.h>
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#include <hardware/dma.h>
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#include "audio_i2s.pio.h"
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typedef struct i2s_config
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{
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uint32_t sample_freq;
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uint16_t channel_count;
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uint8_t data_pin;
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uint8_t clock_pin_base;
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PIO pio;
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uint8_t sm;
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uint8_t dma_channel;
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uint16_t dma_trans_count;
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uint16_t *dma_buf;
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} i2s_config_t;
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i2s_config_t i2s_get_default_config(void);
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void i2s_init(i2s_config_t *i2s_config);
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void i2s_write(const i2s_config_t *i2s_config,const int16_t *samples,const size_t len);
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void i2s_dma_write(i2s_config_t *i2s_config,const int16_t *samples);
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@@ -365,19 +365,17 @@ static void update_noise(int16_t *samples)
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/**
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* SDL2 style audio callback function.
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*/
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void audio_callback(void *userdata, uint8_t *stream, int len)
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void audio_callback(void *userdata, int16_t *stream, size_t len)
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{
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int16_t *samples = (int16_t *)stream;
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/* Appease unused variable warning. */
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(void)userdata;
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memset(stream, 0, len);
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update_square(samples, 0);
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update_square(samples, 1);
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update_wave(samples);
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update_noise(samples);
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update_square(stream, 0);
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update_square(stream, 1);
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update_wave(stream);
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update_noise(stream);
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}
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static void chan_trigger(uint_fast8_t i)
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@@ -9,19 +9,20 @@
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#include <stdint.h>
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#define AUDIO_SAMPLE_RATE 32768
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#define AUDIO_SAMPLE_RATE 44100
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#define DMG_CLOCK_FREQ 4194304.0
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#define SCREEN_REFRESH_CYCLES 70224.0
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#define VERTICAL_SYNC (DMG_CLOCK_FREQ/SCREEN_REFRESH_CYCLES)
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#define AUDIO_SAMPLES ((unsigned)(AUDIO_SAMPLE_RATE / VERTICAL_SYNC))
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#define AUDIO_BUFFER_SIZE_BYTES (AUDIO_SAMPLES*4)
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/**
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* Fill allocated buffer "data" with "len" number of 32-bit floating point
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* samples (native endian order) in stereo interleaved format.
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*/
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void audio_callback(void *ptr, uint8_t *data, int len);
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void audio_callback(void *ptr, int16_t *data, size_t len);
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/**
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* Read audio register at given address "addr".
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+36
-8
@@ -13,11 +13,11 @@
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* PERFORMANCE OF THIS SOFTWARE.
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*/
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// Peanut-GB emulator settings
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#define ENABLE_LCD 1
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#ifndef ENABLE_SOUND
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# define ENABLE_SOUND 0
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#endif
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#define ENABLE_SOUND 1
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#define PEANUT_GB_HIGH_LCD_ACCURACY 1
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#define PEANUT_GB_USE_BIOS 0
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/* Use DMA for all drawing to LCD. Benefits aren't fully realised at the moment
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* due to busy loops waiting for DMA completion. */
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@@ -40,6 +40,7 @@
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#include <string.h>
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/* RP2040 Headers */
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#include <hardware/pio.h>
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#include <hardware/clocks.h>
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#include <hardware/dma.h>
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#include <hardware/spi.h>
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@@ -55,8 +56,10 @@
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/* Project headers */
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#include "hedley.h"
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#include "minigb_apu.h"
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#include "peanut_gb.h"
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#include "mk_ili9225.h"
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#include "i2s.h"
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/* GPIO Connections. */
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#define GPIO_UP 2
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@@ -75,6 +78,15 @@
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#define GPIO_RST 21
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#define GPIO_LED 22
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#if ENABLE_SOUND
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// Global variables for audio task
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// stream contains N=AUDIO_SAMPLES samples
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// each sample is 32 bits
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// (16 bits for the left channel + 16 bits for the right channel in stereo interleaved format)
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// This is intended to be played at AUDIO_SAMPLE_RATE Hz
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uint16_t *stream;
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#endif
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/* DMA channel for LCD communication. */
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static uint dma_lcd;
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/* Definition of ROM data variable. Must be declared like:
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@@ -206,6 +218,7 @@ void core1_irq_dma_lcd_end_transfer(void)
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dma_channel_acknowledge_irq0(dma_lcd);
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}
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#if ENABLE_LCD
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void core1_lcd_draw_line(const uint_fast8_t line)
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{
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const uint16_t palette[3][4] = {
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@@ -317,6 +330,7 @@ void main_core1(void)
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HEDLEY_UNREACHABLE();
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}
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#endif
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#if ENABLE_LCD
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void lcd_draw_line(struct gb_s *gb, const uint8_t pixels[LCD_WIDTH],
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@@ -422,8 +436,10 @@ int main(void)
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spi_set_format(spi0, 16, SPI_CPOL_0, SPI_CPHA_0, SPI_MSB_FIRST);
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/* Start Core1, which processes requests to the LCD. */
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#if ENABLE_LCD
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putstdio("CORE1 ");
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multicore_launch_core1(main_core1);
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#endif
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/* Initialise GB context. */
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memcpy(rom_bank0, rom, sizeof(rom_bank0));
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@@ -469,7 +485,20 @@ int main(void)
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//gb.direct.interlace = 1;
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#endif
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#if ENABLE_SOUND
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// Allocate memory for the stream buffer
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stream=malloc(AUDIO_BUFFER_SIZE_BYTES);
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assert(stream!=NULL);
|
||||
memset(stream,0,AUDIO_BUFFER_SIZE_BYTES); // Zero out the stream buffer
|
||||
|
||||
// Initialize I2S sound driver
|
||||
i2s_config_t i2s_config = i2s_get_default_config();
|
||||
i2s_config.sample_freq=AUDIO_SAMPLE_RATE;
|
||||
i2s_config.dma_trans_count =AUDIO_SAMPLES;
|
||||
i2s_init(&i2s_config);
|
||||
|
||||
// Initialize audio emulation
|
||||
audio_init();
|
||||
|
||||
putstdio("AUDIO ");
|
||||
#endif
|
||||
|
||||
@@ -479,9 +508,6 @@ int main(void)
|
||||
while(1)
|
||||
{
|
||||
int input;
|
||||
#if ENABLE_SOUND
|
||||
static uint16_t stream[1098];
|
||||
#endif
|
||||
|
||||
gb.gb_frame = 0;
|
||||
|
||||
@@ -492,7 +518,9 @@ int main(void)
|
||||
|
||||
frames++;
|
||||
#if ENABLE_SOUND
|
||||
audio_callback(NULL, stream, 1098);
|
||||
audio_callback(NULL, stream, AUDIO_BUFFER_SIZE_BYTES);
|
||||
// i2s_write(&i2s_config,stream,AUDIO_SAMPLES);
|
||||
i2s_dma_write(&i2s_config, stream);
|
||||
#endif
|
||||
|
||||
/* Update buttons state */
|
||||
|
||||
Reference in New Issue
Block a user