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smokkusmokku
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Replace SID with SGU-1 Sound Generator Unit 1
1 parent 0b8f1f6 commit a98e84c

11 files changed

Lines changed: 795 additions & 53 deletions

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‎CMakeLists.txt‎

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@@ -35,6 +35,7 @@ add_executable(emu
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src/chips/pwm.c
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src/chips/cgia.c
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src/chips/ria816.c
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src/chips/sgu1.cc
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src/chips/tca6416a.c
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src/systems/x65.c
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src/x65.c
@@ -47,6 +48,7 @@ add_executable(emu
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src/ui/ui_app_log.cc
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src/ui/ui_x65.cc
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src/util/ringbuffer.c
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src/chips/su/su.cpp
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${CMAKE_CURRENT_BINARY_DIR}/version.c
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)
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target_link_libraries(emu

‎src/chips/sgu1.cc‎

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#include "./sgu1.h"
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#include "./su/su.h"
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#include <string.h>
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#ifdef _MSC_VER
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#define _USE_MATH_DEFINES
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#endif
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#include <math.h> /* tanh */
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#ifndef CHIPS_ASSERT
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#include <assert.h>
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#define CHIPS_ASSERT(c) assert(c)
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#endif
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/* extract 8-bit data bus from 64-bit pins */
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#define SGU1_GET_DATA(p) ((uint8_t)(((p) & 0xFF0000ULL) >> 16))
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/* merge 8-bit data bus value into 64-bit pins */
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#define SGU1_SET_DATA(p, d) \
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{ p = (((p) & ~0xFF0000ULL) | (((d) << 16) & 0xFF0000ULL)); }
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/* fixed point precision for sample period */
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#define SGU1_FIXEDPOINT_SCALE (16)
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/* move bit into first position */
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#define SGU1_BIT(val, bitnr) ((val >> bitnr) & 1)
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#define SGU_SU ((SoundUnit*)(sgu->su))
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void sgu1_init(sgu1_t* sgu, const sgu1_desc_t* desc) {
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CHIPS_ASSERT(sid && desc);
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CHIPS_ASSERT(desc->tick_hz > 0);
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CHIPS_ASSERT(desc->sound_hz > 0);
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memset(sgu, 0, sizeof(*sgu));
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sgu->sound_hz = desc->sound_hz;
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sgu->sample_period = (desc->tick_hz * SGU1_FIXEDPOINT_SCALE) / desc->sound_hz;
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sgu->sample_counter = sgu->sample_period;
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sgu->sample_mag = desc->magnitude;
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sgu->su = new SoundUnit();
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SGU_SU->Init();
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}
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void sgu1_reset(sgu1_t* sgu) {
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CHIPS_ASSERT(sid);
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SGU_SU->Reset();
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sgu->sample_counter = sgu->sample_period;
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sgu->sample = 0.0f;
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sgu->pins = 0;
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}
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/* tick the sound generation, return true when new sample ready */
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static uint64_t _sgu1_tick(sgu1_t* sgu, uint64_t pins) {
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/* new sample? */
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sgu->sample_counter -= SGU1_FIXEDPOINT_SCALE;
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if (sgu->sample_counter <= 0) {
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sgu->sample_counter += sgu->sample_period;
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short l, r;
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SGU_SU->NextSample(&l, &r);
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sgu->sample = (float)(l + r) / 32768.0f * sgu->sample_mag;
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pins |= SGU1_SAMPLE;
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}
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else {
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pins &= ~SGU1_SAMPLE;
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}
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return pins;
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}
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/* read a register */
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static uint64_t _sgu1_read(sgu1_t* sgu, uint64_t pins) {
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uint8_t reg = pins & SGU1_ADDR_MASK;
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uint8_t data = ((unsigned char*)SGU_SU->chan)[reg];
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SGU1_SET_DATA(pins, data);
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return pins;
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}
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/* write a register */
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static void _sgu1_write(sgu1_t* sgu, uint64_t pins) {
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uint8_t reg = pins & SGU1_ADDR_MASK;
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uint8_t data = SGU1_GET_DATA(pins);
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((unsigned char*)SGU_SU->chan)[reg] = data;
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}
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/* the all-in-one tick function */
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uint64_t sgu1_tick(sgu1_t* sgu, uint64_t pins) {
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CHIPS_ASSERT(sid);
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/* first perform the regular per-tick actions */
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pins = _sgu1_tick(sgu, pins);
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/* register read/write */
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if (pins & SGU1_CS) {
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if (pins & SGU1_RW) {
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pins = _sgu1_read(sgu, pins);
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}
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else {
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_sgu1_write(sgu, pins);
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}
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}
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sgu->pins = pins;
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return pins;
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}

‎src/chips/sgu1.h‎

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#pragma once
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/*#
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# sgu1.h
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SGU-1 Sound Generator Unit 1 emulation
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## Emulated Pins
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***********************************
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* +-----------+ *
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* CS --->| |<--- A0 *
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* RW --->| |... *
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* | |<--- A4 *
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* | SGU-1 | *
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* | |<--> D0 *
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* | |... *
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* | |<--> D7 *
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* | | *
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* +-----------+ *
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***********************************
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The emulation has an additional "virtual pin" which is set to active
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whenever a new sample is ready (SGU1_SAMPLE).
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## Links
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-
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## 0BSD license
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Copyright (c) 2025 Tomasz Sterna
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Permission to use, copy, modify, and/or distribute this software for any
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purpose with or without fee is hereby granted.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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#*/
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#include <stdint.h>
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#include <stdbool.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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// address bus pins A0..A5
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#define SGU1_PIN_A0 (0)
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#define SGU1_PIN_A1 (1)
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#define SGU1_PIN_A2 (2)
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#define SGU1_PIN_A3 (3)
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#define SGU1_PIN_A4 (4)
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#define SGU1_PIN_A5 (5)
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// data bus pins D0..D7
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#define SGU1_PIN_D0 (16)
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#define SGU1_PIN_D1 (17)
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#define SGU1_PIN_D2 (18)
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#define SGU1_PIN_D3 (19)
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#define SGU1_PIN_D4 (20)
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#define SGU1_PIN_D5 (21)
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#define SGU1_PIN_D6 (22)
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#define SGU1_PIN_D7 (23)
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// shared control pins
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#define SGU1_PIN_RW (24) /* same as M6502_RW */
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// chip-specific pins
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#define SGU1_PIN_CS (40) /* chip-select */
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#define SGU1_PIN_SAMPLE (41) /* virtual "audio sample ready" pin */
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// pin bit masks
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#define SGU1_A0 (1ULL << SGU1_PIN_A0)
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#define SGU1_A1 (1ULL << SGU1_PIN_A1)
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#define SGU1_A2 (1ULL << SGU1_PIN_A2)
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#define SGU1_A3 (1ULL << SGU1_PIN_A3)
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#define SGU1_A4 (1ULL << SGU1_PIN_A4)
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#define SGU1_A5 (1ULL << SGU1_PIN_A5)
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#define SGU1_ADDR_MASK (0x3F)
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#define SGU1_D0 (1ULL << SGU1_PIN_D0)
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#define SGU1_D1 (1ULL << SGU1_PIN_D1)
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#define SGU1_D2 (1ULL << SGU1_PIN_D2)
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#define SGU1_D3 (1ULL << SGU1_PIN_D3)
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#define SGU1_D4 (1ULL << SGU1_PIN_D4)
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#define SGU1_D5 (1ULL << SGU1_PIN_D5)
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#define SGU1_D6 (1ULL << SGU1_PIN_D6)
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#define SGU1_D7 (1ULL << SGU1_PIN_D7)
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#define SGU1_RW (1ULL << SGU1_PIN_RW)
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#define SGU1_CS (1ULL << SGU1_PIN_CS)
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#define SGU1_SAMPLE (1ULL << SGU1_PIN_SAMPLE)
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// channel registers
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#define SGU1_CHAN_FREQ_LO (0)
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#define SGU1_CHAN_FREQ_HI (1)
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#define SGU1_CHAN_VOL (2)
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#define SGU1_CHAN_PAN (3)
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#define SGU1_CHAN_FLAGS0 (4)
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#define SGU1_CHAN_FLAGS1 (5)
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#define SGU1_CHAN_CUTOFF_LO (6)
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#define SGU1_CHAN_CUTOFF_HI (7)
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#define SGU1_CHAN_DUTY (8)
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#define SGU1_CHAN_RESON (9)
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#define SGU1_CHAN_PCMPOS_LO (10)
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#define SGU1_CHAN_PCMPOS_HI (11)
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#define SGU1_CHAN_PCMBND_LO (12)
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#define SGU1_CHAN_PCMBND_HI (13)
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#define SGU1_CHAN_PCMRST_LO (14)
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#define SGU1_CHAN_PCMRST_HI (15)
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#define SGU1_CHAN_SWFREQ_SPEED_LO (16)
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#define SGU1_CHAN_SWFREQ_SPEED_HI (17)
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#define SGU1_CHAN_SWFREQ_AMT (18)
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#define SGU1_CHAN_SWFREQ_BOUND (19)
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#define SGU1_CHAN_SWVOL_SPEED_LO (20)
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#define SGU1_CHAN_SWVOL_SPEED_HI (21)
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#define SGU1_CHAN_SWVOL_AMT (22)
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#define SGU1_CHAN_SWVOL_BOUND (23)
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#define SGU1_CHAN_SWCUT_SPEED_LO (24)
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#define SGU1_CHAN_SWCUT_SPEED_HI (25)
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#define SGU1_CHAN_SWCUT_AMT (26)
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#define SGU1_CHAN_SWCUT_BOUND (27)
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#define SGU1_CHAN_SPECIAL1C (28)
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#define SGU1_CHAN_SPECIAL1D (29)
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#define SGU1_CHAN_RESTIMER_LO (20)
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#define SGU1_CHAN_RESTIMER_HI (31)
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// setup parameters for sgu1_init()
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typedef struct {
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int tick_hz; // frequency at which sgu1_tick() will be called in Hz
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int sound_hz; // sound sample frequency
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float magnitude; // output sample magnitude (0=silence to 1=max volume)
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} sgu1_desc_t;
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// tsu instance state
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typedef struct {
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int sound_hz;
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// sound unit instance
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void* su;
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// sample generation state
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int sample_period;
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int sample_counter;
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float sample_mag;
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float sample;
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// debug inspection
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uint64_t pins;
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} sgu1_t;
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// initialize a new sgu1_t instance
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void sgu1_init(sgu1_t* sgu, const sgu1_desc_t* desc);
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// reset a sgu1_t instance
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void sgu1_reset(sgu1_t* sgu);
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// tick a sgu1_t instance
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uint64_t sgu1_tick(sgu1_t* sgu, uint64_t pins);
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#ifdef __cplusplus
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} // extern "C"
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#endif

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