Mostly working bufferless SB with CD

polpo · polpo · commit b07642786325 · 2025-07-28T21:56:41.000-06:00
diff --git a/sw/CMakeLists.txt b/sw/CMakeLists.txt
@@ -57,7 +57,17 @@ endfunction()
 
 # Global definitions across all targets
 add_compile_definitions(
-    RP2_CLOCK_SPEED=366000
+    # 370MHz is extremely closely evenly divisible by 44100Hz
+    RP2_CLOCK_SPEED=370000
+    SYS_CLK_HZ=370000000
+    # Manually set up PLLs because of non-default REFDIV
+    PLL_SYS_REFDIV=2
+    PLL_SYS_VCO_FREQ_HZ=1110000000
+    PLL_SYS_POSTDIV1=3
+    PLL_SYS_POSTDIV2=1
+    # Set voltage before main so no need to do so on the fly
+    SYS_CLK_VREG_VOLTAGE_AUTO_ADJUST=1
+    SYS_CLK_VREG_VOLTAGE_MIN=VREG_VOLTAGE_1_25
     PICO_DEFAULT_UART=0
     PICO_DEFAULT_UART_TX_PIN=28
     PICO_DEFAULT_UART_RX_PIN=-1
@@ -77,6 +87,7 @@ function(config_target TARGET_NAME MULTIFW)
         PICO_AUDIO_I2S_DATA_PIN=16
         PICO_AUDIO_I2S_CLOCK_PIN_BASE=17
         PICO_AUDIO_I2S_PIO=1
+        PICO_AUDIO_I2S_SM=3
         M62429_PIO=1
     )
 
@@ -235,7 +246,7 @@ endfunction()
 # Build SB firmware
 function(build_sb TARGET_NAME MULTIFW)
     set(USB_JOYSTICK TRUE)
-    set(SOUND_MPU TRUE)
+    set(SOUND_MPU FALSE)
     set(SOUND_OPL TRUE)
     set(CDROM TRUE)
     config_target(${TARGET_NAME} ${MULTIFW})
@@ -245,11 +256,14 @@ function(build_sb TARGET_NAME MULTIFW)
         sbplay.cpp
         isa_dma.c
         audio_fifo.c
+        audio_i2s_minimal.c
     )
     target_compile_definitions(${TARGET_NAME} PRIVATE
         SOUND_SB=1
         SOUND_DSP=1
-        # SB_BUFFERLESS=1
+        SB_BUFFERLESS=1
+        SB_BUFFERLESS_NG=1
+        USE_CD_AUDIO_FIFO=1
     )
     pico_generate_pio_header(${TARGET_NAME} ${CMAKE_CURRENT_LIST_DIR}/isa_dma.pio)
 endfunction()
diff --git a/sw/audio_fifo.c b/sw/audio_fifo.c
@@ -1,3 +1,20 @@
+/*
+ *  Copyright (C) 2025  Ian Scott
+ *
+ *  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.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
 /**
  * audio_fifo.c - Implementation of shared FIFO functionality
  *
diff --git a/sw/audio_fifo.h b/sw/audio_fifo.h
@@ -1,3 +1,20 @@
+/*
+ *  Copyright (C) 2025  Ian Scott
+ *
+ *  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.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
 /**
  * audio_fifo.h - Shared header for audio producer and consumer
  *
@@ -49,6 +66,10 @@ bool fifo_add_sample(audio_fifo_t *fifo, audio_sample_t sample);
 bool fifo_add_samples(audio_fifo_t *fifo, const audio_sample_t *samples_buffer, uint32_t num_samples_to_add);
 
 uint32_t fifo_take_samples(audio_fifo_t *fifo, uint32_t num_samples);
+
+inline uint32_t fifo_free_space(audio_fifo_t *fifo) {
+   return AUDIO_FIFO_SIZE - fifo->samples_in_fifo;
+}
 // Helper for consumer to get one sample, this is a more fundamental FIFO op
 
 #ifdef __cplusplus
diff --git a/sw/audio_i2s_minimal.c b/sw/audio_i2s_minimal.c
@@ -0,0 +1,54 @@
+/*
+ *  Copyright (C) 2025  Ian Scott
+ *
+ *  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.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#include <hardware/clocks.h>
+#include <audio_i2s.pio.h>
+#include "audio_i2s_minimal.h"
+
+#define audio_pio __CONCAT(pio, PICO_AUDIO_I2S_PIO)
+#define GPIO_FUNC_PIOx __CONCAT(GPIO_FUNC_PIO, PICO_AUDIO_I2S_PIO)
+
+void audio_i2s_minimal_setup(const audio_i2s_config_t *config, uint32_t sample_rate) {
+    uint func = GPIO_FUNC_PIOx;
+    gpio_set_function(config->data_pin, func);
+    gpio_set_function(config->clock_pin_base, func);
+    gpio_set_function(config->clock_pin_base + 1, func);
+
+#if PICO_PIO_USE_GPIO_BASE
+    if(config->data_pin >= 32 || config->clock_pin_base + 1 >= 32) {
+        pio_set_gpio_base(audio_pio, 16);
+    }
+#endif
+    uint8_t sm = config->pio_sm;
+    pio_sm_claim(audio_pio, sm);
+
+    const struct pio_program *program =
+#if PICO_AUDIO_I2S_CLOCK_PINS_SWAPPED
+        &audio_i2s_swapped_program
+#else
+        &audio_i2s_program
+#endif
+        ;
+    uint offset = pio_add_program(audio_pio, program);
+
+    audio_i2s_program_init(audio_pio, sm, offset, config->data_pin, config->clock_pin_base);
+
+    uint32_t system_clock_frequency = clock_get_hz(clk_sys);
+    uint32_t divider = system_clock_frequency * 4 / sample_rate; // avoid arithmetic overflow
+    pio_sm_set_clkdiv_int_frac(audio_pio, sm, divider >> 8u, divider & 0xffu);
+    pio_sm_set_enabled(audio_pio, sm, true);
+}
diff --git a/sw/audio_i2s_minimal.h b/sw/audio_i2s_minimal.h
@@ -0,0 +1,35 @@
+/*
+ *  Copyright (C) 2025  Ian Scott
+ *
+ *  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.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#pragma once
+
+#include <pico/audio_i2s.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Alternative setup for pico_extras' audio_i2s library that does not set up DMA.
+ * This allows for a minimal set up audio to be sent to the PIO sample by sample,
+ * enabling a simpler interface with a sample clock IRQ, other buffering arrangement, etc.
+ */
+void audio_i2s_minimal_setup(const audio_i2s_config_t *config, uint32_t sample_rate);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
diff --git a/sw/pico_pic.c b/sw/pico_pic.c
@@ -50,6 +50,6 @@ void PIC_RemoveEvent(PIC_TimerEvent* event) {
 }
 
 void PIC_Init() {
-    alarm_pool = alarm_pool_create(2, PICO_TIME_DEFAULT_ALARM_POOL_MAX_TIMERS);
-    irq_set_priority(TIMER_IRQ_2, PICO_HIGHEST_IRQ_PRIORITY);
+    alarm_pool = alarm_pool_create_with_unused_hardware_alarm(PICO_TIME_DEFAULT_ALARM_POOL_MAX_TIMERS);
+    irq_set_priority(hardware_alarm_get_irq_num(alarm_pool_timer_alarm_num(alarm_pool)), PICO_HIGHEST_IRQ_PRIORITY);
 }
diff --git a/sw/picogus.cpp b/sw/picogus.cpp
@@ -71,7 +71,7 @@ void play_adlib(void);
 extern "C" int OPL_Pico_Init(unsigned int);
 extern "C" unsigned int OPL_Pico_PortRead(opl_port_t);
 #include "cmd_buffers.h"
-cms_buffer_t opl_buffer = { {0}, 0, 0 };
+cms_buffer_t opl_cmd_buffer = { {0}, 0, 0 };
 #endif
 
 #ifdef CDROM
@@ -664,13 +664,13 @@ __force_inline void handle_iow(void) {
             // Fast write
             pio_sm_put(pio0, IOW_PIO_SM, IO_END);
             // pio_sm_put(pio0, IOW_PIO_SM, IO_WAIT);
-            opl_buffer.cmds[opl_buffer.head].addr = (uint16_t)(iow_read & 0xFF);
+            opl_cmd_buffer.cmds[opl_cmd_buffer.head].addr = (uint16_t)(iow_read & 0xFF);
             // Fast write - return early as we've already written 0x0u to the PIO
             return;
             break;
         case 0x9:
             pio_sm_put(pio0, IOW_PIO_SM, IO_WAIT);
-            opl_buffer.cmds[opl_buffer.head++].data = (uint8_t)(iow_read & 0xFF);
+            opl_cmd_buffer.cmds[opl_cmd_buffer.head++].data = (uint8_t)(iow_read & 0xFF);
             break;
         // DSP ports
         default:
@@ -694,15 +694,15 @@ __force_inline void handle_iow(void) {
         if ((port & 1) == 0) {
             // Fast write
             pio_sm_put(pio0, IOW_PIO_SM, IO_END);
-            opl_buffer.cmds[opl_buffer.head].addr = (uint16_t)(iow_read & 0xFF);
+            opl_cmd_buffer.cmds[opl_cmd_buffer.head].addr = (uint16_t)(iow_read & 0xFF);
             // Fast write - return early as we've already written 0x0u to the PIO
             return;
         } else {
             pio_sm_put(pio0, IOW_PIO_SM, IO_WAIT);
             if (settings.SB.oplSpeedSensitive) {
                 busy_wait_us(1); // busy wait for speed sensitive games
             }
-            opl_buffer.cmds[opl_buffer.head++].data = (uint8_t)(iow_read & 0xFF);
+            opl_cmd_buffer.cmds[opl_cmd_buffer.head++].data = (uint8_t)(iow_read & 0xFF);
         }
     } else // if follows down below
 #endif // SOUND_OPL
@@ -841,7 +841,7 @@ __force_inline void handle_ior(void) {
         switch (port - settings.SB.basePort) {
         case 0x8:
             // wait for OPL buffer to process
-            while (opl_buffer.tail != opl_buffer.head) {
+            while (opl_cmd_buffer.tail != opl_cmd_buffer.head) {
                 tight_loop_contents();
             }
             pio_sm_put(pio0, IOR_PIO_SM, IOR_SET_VALUE | OPL_Pico_PortRead(OPL_REGISTER_PORT));
@@ -867,7 +867,7 @@ __force_inline void handle_ior(void) {
         // Tell PIO to wait for data
         pio_sm_put(pio0, IOR_PIO_SM, IO_WAIT);
         // wait for OPL buffer to process
-        while (opl_buffer.tail != opl_buffer.head) {
+        while (opl_cmd_buffer.tail != opl_cmd_buffer.head) {
             tight_loop_contents();
         }
         pio_sm_put(pio0, IOR_PIO_SM, IOR_SET_VALUE | OPL_Pico_PortRead(OPL_REGISTER_PORT));
@@ -988,6 +988,7 @@ __force_inline bool ior_has_data() {
 #include "hardware/structs/xip_ctrl.h"
 int main()
 {
+    busy_wait_ms(250);
 #ifdef ASYNC_UART
     stdio_async_uart_init_full(UART_ID, BAUD_RATE, UART_TX_PIN, UART_RX_PIN);
 #else
@@ -1041,31 +1042,6 @@ int main()
         BOARD_TYPE = PICOGUS_2;
     }
     gpio_set_mask(LED_PIN);
-    printf("Waiting for board to stabilize... ");
-    busy_wait_ms(250);
-    // Overclock!
-    printf("Overclocking... ");
-    vreg_set_voltage(VREG_VOLTAGE_1_25);
-    // vreg_set_voltage(VREG_VOLTAGE_1_15);
-    busy_wait_ms(250);
-    set_sys_clock_khz(rp2_clock, true);
-    busy_wait_ms(250);
-    gpio_xor_mask(LED_PIN);
-#ifdef ASYNC_UART
-    uart_init(UART_ID, 0);
-#else
-    stdio_init_all();
-#endif
-    puts("Done. Continuing!");
-
-    // Set clk_peri to use the XOSC
-    // clock_configure(clk_peri,
-    //                 0,
-    //                 CLOCKS_CLK_PERI_CTRL_AUXSRC_VALUE_XOSC_CLKSRC,
-    //                 12 * MHZ,
-    //                 12 * MHZ);
-    // clock_configure(clk_peri, 0, CLOCKS_CLK_PERI_CTRL_AUXSRC_VALUE_CLK_SYS,
-    //         12 * MHZ, 12 * MHZ);
 
     if (BOARD_TYPE == PICOGUS_2) {
         // Create new interface to M62429 digital volume control
diff --git a/sw/sbplay.cpp b/sw/sbplay.cpp

Original file line number	Diff line number	Diff line change
`@@ -50,6 +50,6 @@ void PIC_RemoveEvent(PIC_TimerEvent* event) {`
`50`	`50`	`}`
`51`	`51`
`52`	`52`	`void PIC_Init() {`
`53`		`- alarm_pool = alarm_pool_create(2, PICO_TIME_DEFAULT_ALARM_POOL_MAX_TIMERS);`
`54`		`- irq_set_priority(TIMER_IRQ_2, PICO_HIGHEST_IRQ_PRIORITY);`
	`53`	`+ alarm_pool = alarm_pool_create_with_unused_hardware_alarm(PICO_TIME_DEFAULT_ALARM_POOL_MAX_TIMERS);`
	`54`	`+ irq_set_priority(hardware_alarm_get_irq_num(alarm_pool_timer_alarm_num(alarm_pool)), PICO_HIGHEST_IRQ_PRIORITY);`
`55`	`55`	`}`