Feat: add sine wave lookup table generation

Refs: #12

README.org

@@ -7,7 +7,13 @@ This project aims to create a generic esp32-s3 based eurorack modular unit—rep
 - I/O
   - 4 channel input
   - 4 channel output
-  - Output signal 0 -> +5V
+  - Output signal 0 -> ~+5V
   - 2 Rotary encoder switches
   - 4 buttons
 - 2.2in TFT LCD Display
+
+* Hardware
+** MCP4728 Quad 12bit I2C DAC
+- [[https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/DataSheets/22187E.pdf][Datasheet]]
+- [[https://learn.adafruit.com/adafruit-mcp4728-i2c-quad-dac][Adafruit Info Page]]
+- 0 -> ~+5V out

src/main/CMakeLists.txt

@@ -1,2 +1,2 @@
-idf_component_register(SRCS "esp32_eurorack_generic.c"
+idf_component_register(SRCS "esp32_eurorack_generic.c" "wavetable.c"
                     INCLUDE_DIRS ".")

src/main/esp32_eurorack_generic.c

@@ -1,6 +1,129 @@
 #include <stdio.h>
+#include <stdint.h>
 
+#include "driver/gpio.h"
+#include "driver/i2c.h"
+#include "esp_err.h"
+#include "esp_log.h"
+#include "freertos/portmacro.h"
+#include "hal/i2c_types.h"
+
+#include "wavetable.h"
+
+/* DAC Peripheral Config */
+#define DAC_SCL_PIN 12
+#define DAC_SDA_PIN 13
+#define DAC_LDAC_PIN 14
+
+#define DAC_ADDR 0x64 /* I2C Address of DAC */
+#define DAC_VREF 0x00 /* Use Vdd as reference voltage */
+#define DAC_PD 0x00 /* Full power mode */
+#define DAC_GAIN 0x00 /* Since we use external Vref, this doesn't matter */
+
+#define ACK_EN 0x1 /* Enable i2c acknowledgment check */
+#define ACK_DIS 0x0 /* Disable i2c acknowledgment check */
+#define ACK_VAL 0x0  /* i2c acknowledgment value */
+#define NACK_VAL 0x1 /* i2c negative-acknowledgment value */
+
+static const i2c_port_t I2C_MASTER_PORT = 0;
+
+static const char *TAG = "EERG";
+
+
+/* Initialize and configure I2C DAC */
+static void dac_init(void)
+{
+  ESP_LOGI(TAG, "Initializing DAC I2C connection");
+
+  /* Configure µC as I2C master */
+  i2c_config_t i2c_conf = {
+    .mode = I2C_MODE_MASTER,
+    .scl_io_num = DAC_SCL_PIN,
+    .sda_io_num = DAC_SDA_PIN,
+    .master.clk_speed = 400000 /* 400kHz for i2c fast mode */
+
+  };
+  i2c_param_config(I2C_MASTER_PORT, &i2c_conf);
+
+  /* Install i2c driver */
+  ESP_ERROR_CHECK(i2c_driver_install(I2C_MASTER_PORT, i2c_conf.mode, 0, 0, 0));
+
+  /* Setup LDAC pin with GPIO. Tied low */
+  gpio_reset_pin(DAC_LDAC_PIN);
+  gpio_set_direction(DAC_LDAC_PIN, GPIO_MODE_OUTPUT);
+  gpio_set_level(DAC_LDAC_PIN, 0);
+}
+
+/* Tests for acknowledgment of i2c DAC. Return ESP_OK if so */
+static esp_err_t dac_ack_test(void)
+{
+  ESP_LOGI(TAG, "Testing I2C DAC");
+  /* Create i2c command handle */
+  i2c_cmd_handle_t cmd = i2c_cmd_link_create();
+  i2c_master_start(cmd);
+  i2c_master_write_byte(cmd, (DAC_ADDR << 1) | I2C_MASTER_READ, ACK_EN); /* R/W byte is LSB of DAC address */
+  i2c_master_stop(cmd);
+  esp_err_t ret = i2c_master_cmd_begin(I2C_MASTER_PORT, cmd, 1000 / portTICK_PERIOD_MS);
+  i2c_cmd_link_delete(cmd);
+
+  return ret;
+}
+
+/* Brings all DAC output channels from 0 -> ~+5V */
+static esp_err_t dac_out_test(void)
+{
+  esp_err_t ret;
+  uint16_t test_value = 0; /* The value sent to DAC input registers */
+  i2c_cmd_handle_t cmd;
+
+  for (uint16_t i = 0; i < 4096; i++){
+
+    test_value = i;
+
+    cmd = i2c_cmd_link_create();
+    i2c_master_start(cmd);
+    i2c_master_write_byte(cmd, (DAC_ADDR << 1) | I2C_MASTER_WRITE, ACK_EN); /* R/W byte is LSB of DAC address */
+    i2c_master_write_byte(cmd, 0x50, ACK_EN); /* Multi-write to all channels */
+
+    /* For each channel [A-D] write 2 bytes to input register */
+    /* V_ref + PD1 + PD0 + Gx + D11-D8 | D7-D0 */
+    for (uint8_t i = 0; i < 4; i++) {
+      uint8_t bytes[2];
+      bytes[0] = ((uint8_t) DAC_VREF << 7) | ((uint8_t) DAC_PD << 5) | ((uint8_t) DAC_GAIN << 4) | (test_value >> 8);
+      bytes[1] = test_value;
+      i2c_master_write_byte(cmd, bytes[0], ACK_EN);
+      i2c_master_write_byte(cmd, bytes[1], ACK_EN);
+    }
+
+    i2c_master_stop(cmd);
+
+    /* Issue the multi-write command */
+    /* TODO need to create array of returns and check them for error */
+    ret = i2c_master_cmd_begin(I2C_MASTER_PORT, cmd, 1000 / portTICK_PERIOD_MS);
+    i2c_cmd_link_delete(cmd);
+  }
+  return ret;
+}
+
+/* Main application entrance */
 void app_main(void)
 {
+  /* Initialize and configure I2C DAC */
+  dac_init();
 
+  /* Test DAC */
+  esp_err_t ret = dac_ack_test();
+  if (ret != ESP_OK){
+    ESP_LOGE(TAG, "Failed to initialize DAC");
+  } else {
+    ESP_LOGI(TAG, "Sucessfully initialized DAC");
+  }
+
+  /* Generate wave tables */
+  gen_wavetables();
+
+  /* Loop to test DAC output */
+  while (1) {
+    dac_out_test();
+  }
 }

src/main/wavetable.c

@@ -0,0 +1,35 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include "esp_log.h"
+
+#include "wavetable.h"
+
+#define SAMPLE_RATE 22000 /* 22kHz  */
+#define FREQ 440
+#define TIME 1
+
+float_t *sin_tbl;
+
+static const char *TAG = "wavetable";
+
+static void gen_sin_table(void)
+{
+  /* Allocate memory */
+  uint16_t table_length = 1024; /* TODO make this accurate to sample rate and frequency */
+  sin_tbl = (float *)malloc(sizeof(float) * table_length);
+
+  /* Loop through values and store in table */
+  for (uint16_t i = 0; i < table_length; i++) {
+    sin_tbl[i] = sin((2 * M_PI * i) / table_length);
+  }
+}
+
+void gen_wavetables(void)
+{
+  ESP_LOGI(TAG, "Generating sine wavetable");
+  gen_sin_table();
+}

src/main/wavetable.h

@@ -0,0 +1,7 @@
+#ifndef WAVETABLE_H_ /* Guard */
+#define WAVETABLE_H_
+
+/* Generates all wavetables */
+void gen_wavetables(void);
+
+#endif