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Initial set of changes to offload the volume controls to the DAC.

This commit is contained in:
george-norton 2023-04-28 09:52:57 +01:00
parent a8f9b522de
commit d7d40af360
2 changed files with 50 additions and 34 deletions
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78
firmware/code/run.c
View File

@ -54,7 +54,7 @@ bqf_mem_t bqf_filters_mem_right[FILTER_STAGES];
static struct {
uint32_t freq;
int16_t volume;
int16_t vol_mul;
int16_t target_volume;
bool mute;
} audio_state = {
.freq = 48000,
@ -92,7 +92,6 @@ static void _as_audio_packet(struct usb_endpoint *ep) {
struct usb_buffer *usb_buffer = usb_current_out_packet_buffer(ep);
int16_t *in = (int16_t *) usb_buffer->data;
int32_t *out = (int32_t *) userbuf;
uint16_t vol_mul = audio_state.vol_mul;
int samples = usb_buffer->data_len / 2;
for (int i = 0; i < samples; i++)
@ -116,10 +115,6 @@ static void _as_audio_packet(struct usb_endpoint *ep) {
// Block until core 1 has finished transforming the data
uint32_t ready = multicore_fifo_pop_blocking();
// Multiply the outgoing signal with the volume multiple
for (int i = 0; i < samples; i++)
out[i] = out[i] * (int32_t) vol_mul;
i2s_stream_write(&i2s_write_obj, userbuf, samples * 4);
// keep on truckin'
@ -154,12 +149,32 @@ void core1_entry() {
// Signal to core 0 that the data has all been transformed
multicore_fifo_push_blocking(CORE1_READY);
// Update the volume if required. We do this from core1 as
// core0 is more heavily loaded, doing this from core0 can
// lead to audio crackling.
if (audio_state.volume != audio_state.target_volume) {
// Volume attenuation:
// 0: 0db (default)
// 55: -100db
// 56..: Mute
uint8_t value = 255 + (audio_state.target_volume / 128);
uint8_t buf[3];
buf[0] = 65; // register addr
buf[1] = value; // data left
buf[2] = value; // data right
i2c_write_blocking(i2c0, PCM_I2C_ADDR, buf, 3, false);
audio_state.volume = audio_state.target_volume;
}
}
}
void setup() {
set_sys_clock_khz(SYSTEM_FREQ / 1000, true);
sleep_ms(100);
// stdio_init_all();
userbuf = malloc(sizeof(uint8_t) * RINGBUF_LEN_IN_BYTES);
@ -185,7 +200,10 @@ void setup() {
gpio_set_dir(PCM3060_RST_PIN, GPIO_OUT);
gpio_put(PCM3060_RST_PIN, true);
i2c_init(i2c0, 50000);
// The PCM3060 supports standard mode (100kbps) or fast mode (400kbps)
// we run in fast mode so we dont block the core for too long while
// updating the volume.
i2c_init(i2c0, 400000);
gpio_set_function(PCM3060_SDA_PIN, GPIO_FUNC_I2C);
gpio_set_function(PCM3060_SCL_PIN, GPIO_FUNC_I2C);
gpio_pull_up(PCM3060_SDA_PIN);
@ -203,6 +221,11 @@ void setup() {
// Don't remove this. Don't do it.
sleep_ms(200);
// Set data format to 16 bit right justified, MSB first
buf[0] = 67; // register addr
buf[1] = 0x03; // data
i2c_write_blocking(i2c0, PCM_I2C_ADDR, buf, 2, false);
// Enable DAC
buf[0] = 64; // register addr
buf[1] = 0xE0; // data
@ -512,22 +535,6 @@ static bool do_get_current(struct usb_setup_packet *setup) {
return false;
}
// todo this seemed like aood guess, but is not correct
uint16_t db_to_vol[91] = {
0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0002, 0x0002,
0x0002, 0x0002, 0x0003, 0x0003, 0x0004, 0x0004, 0x0005, 0x0005,
0x0006, 0x0007, 0x0008, 0x0009, 0x000a, 0x000b, 0x000d, 0x000e,
0x0010, 0x0012, 0x0014, 0x0017, 0x001a, 0x001d, 0x0020, 0x0024,
0x0029, 0x002e, 0x0033, 0x003a, 0x0041, 0x0049, 0x0052, 0x005c,
0x0067, 0x0074, 0x0082, 0x0092, 0x00a4, 0x00b8, 0x00ce, 0x00e7,
0x0104, 0x0124, 0x0147, 0x016f, 0x019c, 0x01ce, 0x0207, 0x0246,
0x028d, 0x02dd, 0x0337, 0x039b, 0x040c, 0x048a, 0x0518, 0x05b7,
0x066a, 0x0732, 0x0813, 0x090f, 0x0a2a, 0x0b68, 0x0ccc, 0x0e5c,
0x101d, 0x1214, 0x1449, 0x16c3, 0x198a, 0x1ca7, 0x2026, 0x2413,
0x287a, 0x2d6a, 0x32f5, 0x392c, 0x4026, 0x47fa, 0x50c3, 0x5a9d,
0x65ac, 0x7214, 0x7fff
};
static bool do_get_minimum(struct usb_setup_packet *setup) {
if ((setup->bmRequestType & USB_REQ_TYPE_RECIPIENT_MASK) == USB_REQ_TYPE_RECIPIENT_INTERFACE) {
switch (setup->wValue >> 8u) {
@ -584,14 +591,19 @@ static void _audio_reconfigure() {
}
static void audio_set_volume(int16_t volume) {
audio_state.volume = volume;
// todo interpolate
volume += CENTER_VOLUME_INDEX * 256;
if (volume < 0)
volume = 0;
if (volume >= count_of(db_to_vol) * 256)
volume = count_of(db_to_vol) * 256 - 1;
audio_state.vol_mul = db_to_vol[((uint16_t)volume) >> 8u];
// volume is in the range 127.9961dB (0x7FFF) .. -127.9961dB (0x8001). 0x8000 = mute
// the old code reported a min..max volume of -90.9961dB (0xA500) .. 0dB (0x0)
if (volume == 0x8000) {
// Mute case
}
else if (volume > (int16_t) MAX_VOLUME) {
volume = MAX_VOLUME;
}
else if (volume < (int16_t) MIN_VOLUME) {
volume = MIN_VOLUME;
}
audio_state.target_volume = volume;
}
static void audio_cmd_packet(struct usb_endpoint *ep) {
@ -603,6 +615,10 @@ static void audio_cmd_packet(struct usb_endpoint *ep) {
switch (audio_control_cmd_t.cs) {
case 1: { // mute
audio_state.mute = buffer->data[0];
uint8_t buf[2];
buf[0] = 68; // register addr
buf[1] = buffer->data[0] ? 0x3 : 0x0; // data
i2c_write_blocking(i2c0, PCM_I2C_ADDR, buf, 2, false);
break;
}
case 2: { // volume

6
firmware/code/run.h
View File

@ -40,10 +40,10 @@
#define ENCODE_DB(x) ((uint16_t)(int16_t)((x)*256))
#define MIN_VOLUME ENCODE_DB(-CENTER_VOLUME_INDEX)
#define MIN_VOLUME ENCODE_DB(-100)
#define DEFAULT_VOLUME ENCODE_DB(0)
#define MAX_VOLUME ENCODE_DB(count_of(db_to_vol)-CENTER_VOLUME_INDEX)
#define VOLUME_RESOLUTION ENCODE_DB(1)
#define MAX_VOLUME ENCODE_DB(0)
#define VOLUME_RESOLUTION ENCODE_DB(0.5f)
typedef struct _audio_device_config {
struct usb_configuration_descriptor descriptor;