diff --git a/oscilloscope.c b/oscilloscope.c
index daafa662dea329e6d874be04b28b93551d5e39ac..4f54617f7428665c5144ce782608dd58c111e477 100644
--- a/oscilloscope.c
+++ b/oscilloscope.c
@@ -12,12 +12,17 @@ int16_t *raw_buffer_a;
int16_t *raw_buffer_b;
bool active_buffer; // 0 for a, 1 for b
unsigned int dma_channel;
-unsigned int dma_irq;
samples_ready_handler_t samples_ready_handler;
volatile int samples_read;
-int16_t sample_buffer[256];
+int16_t sample_buffer[SAMPLE_BUFFER_SIZE];
+/*
+ Lots of this code is derived from
+ https://github.com/raspberrypi/pico-examples/tree/master/adc/dma_capture
+ and
+ https://github.com/ArmDeveloperEcosystem/microphone-library-for-pico
+ */
int main()
{
@@ -37,7 +42,7 @@ int main()
unsigned int num_samples = 0;
- // with the arducam text UPSIDE DOWN,
+ // with the arducam text upside down,
// x is left-to-right on the narrow (max x is on the right)
// y is top-to-bottom on the long (max y is at the bottom)
@@ -45,10 +50,10 @@ int main()
{
while (samples_read == 0) tight_loop_contents();
- for (size_t i = 0; i < 128; i++)
- {
- int16_t sample_value = sample_buffer[i*2];
- ST7735_DrawPixel((sample_value) / 20, i, ST7735_COLOR565(i, 128, 128));
+ for (size_t i = 0; i < 160; i++)
+ {
+ int16_t sample_value = sample_buffer[(256*i)/160];
+ ST7735_DrawPixel((sample_value) / 12, i, ST7735_COLOR565(i, 128, 128));
}
sleep_ms(50);
@@ -77,7 +82,6 @@ void setup_adc()
void setup_dma()
{
-
raw_buffer_a = malloc(SAMPLE_BUFFER_SIZE * sizeof(uint16_t));
raw_buffer_b = malloc(SAMPLE_BUFFER_SIZE * sizeof(uint16_t));
if (raw_buffer_a == NULL || raw_buffer_b == NULL) gpio_put(PICO_DEFAULT_LED_PIN, 1); // bad!
@@ -93,8 +97,6 @@ void setup_dma()
channel_config_set_write_increment(&config, true);
channel_config_set_dreq(&config, DREQ_ADC);
- dma_irq = DMA_IRQ_0;
-
dma_channel_configure(
dma_channel,
&config,
@@ -103,13 +105,12 @@ void setup_dma()
SAMPLE_BUFFER_SIZE,
false
);
-
}
void start_listening()
{
- irq_set_enabled(dma_irq, true);
- irq_set_exclusive_handler(dma_irq, dma_handler);
+ irq_set_enabled(DMA_IRQ_0, true);
+ irq_set_exclusive_handler(DMA_IRQ_0, dma_handler);
dma_channel_set_irq0_enabled(dma_channel, true);
diff --git a/oscilloscope_incomplete.c b/oscilloscope_incomplete.c
new file mode 100644
index 0000000000000000000000000000000000000000..ab14e4a64f6e17e96a4499daa9cfe5fdb5dfdabb
--- /dev/null
+++ b/oscilloscope_incomplete.c
@@ -0,0 +1,140 @@
+#include "oscilloscope.h"
+
+#define ADC_PIN 26
+
+#define BIAS_VOLTAGE 1.25
+#define SAMPLE_RATE 8000
+#define SAMPLE_BUFFER_SIZE 256
+
+const int16_t bias = (BIAS_VOLTAGE * 4095) / 3.3;
+
+int16_t *raw_buffer_a;
+int16_t *raw_buffer_b;
+bool active_buffer; // 0 for a, 1 for b
+unsigned int dma_channel;
+unsigned int dma_irq;
+
+samples_ready_handler_t samples_ready_handler;
+volatile int samples_read;
+int16_t sample_buffer[SAMPLE_BUFFER_SIZE];
+
+/*
+ Lots of this code is derived from
+ https://github.com/raspberrypi/pico-examples/tree/master/adc/dma_capture
+ and
+ https://github.com/ArmDeveloperEcosystem/microphone-library-for-pico
+ */
+
+int main()
+{
+ stdio_init_all();
+ setvbuf(stdout, NULL, _IONBF, 0);
+ sleep_ms(1000);
+
+ // screen init
+ ST7735_Init();
+ ST7735_FillScreen(ST7735_BLACK);
+
+ // microphone setup
+ setup_adc();
+ setup_dma();
+ set_samples_ready_handler(on_samples_ready);
+ start_listening();
+
+ unsigned int num_samples = 0;
+
+ // with the arducam text upside down,
+ // x is left-to-right on the narrow (max x is on the right)
+ // y is top-to-bottom on the long (max y is at the bottom)
+
+ while (true)
+ {
+ // TODO: draw the output (from sample_buffer)
+ }
+}
+
+void start_listening()
+{
+ // TODO: somehow call dma_handler when the samples are ready
+ // also set the adc running
+}
+
+void dma_handler()
+{
+ // TODO: get the samples from DMA into main()
+ // hint: call samples_ready_handler at the end
+}
+
+void setup_adc()
+{
+ adc_gpio_init(ADC_PIN);
+
+ adc_init();
+ adc_select_input(0);
+ adc_fifo_setup(
+ true,
+ true,
+ 1,
+ false,
+ false
+ );
+
+ float clkdiv = (clock_get_hz(clk_adc) / SAMPLE_RATE) - 1;
+ adc_set_clkdiv(clkdiv);
+}
+
+void setup_dma()
+{
+ raw_buffer_a = malloc(SAMPLE_BUFFER_SIZE * sizeof(uint16_t));
+ raw_buffer_b = malloc(SAMPLE_BUFFER_SIZE * sizeof(uint16_t));
+ if (raw_buffer_a == NULL || raw_buffer_b == NULL) gpio_put(PICO_DEFAULT_LED_PIN, 1); // bad!
+
+ active_buffer = 0;
+
+ dma_channel = dma_claim_unused_channel(true);
+ if (dma_channel < 0) gpio_put(PICO_DEFAULT_LED_PIN, 1); // bad, also!
+
+ dma_channel_config config = dma_channel_get_default_config(dma_channel);
+ channel_config_set_transfer_data_size(&config, DMA_SIZE_16);
+ channel_config_set_read_increment(&config, false);
+ channel_config_set_write_increment(&config, true);
+ channel_config_set_dreq(&config, DREQ_ADC);
+
+
+ dma_channel_configure(
+ dma_channel,
+ &config,
+ raw_buffer_a, // start with buffer a
+ &adc_hw->fifo,
+ SAMPLE_BUFFER_SIZE,
+ false
+ );
+
+}
+
+void set_samples_ready_handler(samples_ready_handler_t handler)
+{
+ samples_ready_handler = handler;
+}
+
+int read_samples(int16_t* buffer, size_t samples)
+{
+ uint16_t* in = active_buffer ? raw_buffer_a : raw_buffer_b;
+ int16_t* out = buffer;
+
+ for (size_t i = 0; i < samples; i++)
+ {
+ *out++ = *in++ - bias;
+ }
+
+ return samples;
+}
+
+void on_samples_ready()
+{
+ samples_read = read_samples(sample_buffer, SAMPLE_BUFFER_SIZE);
+}
+
+void debug_write_to_screen(char debug_string[]) {
+ ST7735_WriteString(80, 80, debug_string, Font_16x26, ST7735_RED, ST7735_BLACK);
+}