Real-time Spectrum Analyzer

Lab 7: Spectrum Analyzer in Action

1. โครงสร้างภาพรวมของ Lab

Why? - ทำไมต้องเรียนรู้เรื่องนี้

• Real Hardware: เชื่อมต่อ UI กับ hardware จริง (ADC, PWM)

• Signal Generation: สร้างสัญญาณจริงๆ ออกไปที่ LED

• Interactive Control: ควบคุม parameter ด้วย potentiometer

• Embedded Systems: รวมความรู้ทั้งหมดใน Week 1-5

What? - จะได้เรียนรู้อะไร

1. ADC Integration: อ่านค่า Potentiometer → ควบคุม UI

2. PWM Output: สร้างสัญญาณจริงออก LED3

3. Panel Navigation: Custom panel แทน TabView

4. Real-time Control: Slider sync กับ hardware

5. Phase Accumulator: แปลง waveform → LED brightness

How? - จะทำอย่างไร

1. ศึกษา week5_hw_scope_example.c

2. เข้าใจ ADC mapping (POTEN → frequency/duty)

3. เข้าใจ PWM output (waveform → LED3)

4. Build, Flash และทดสอบกับ hardware จริง

---

2. Hardware Connections

2.1 PSoC Edge E84 Pin Mapping

┌─────────────────────────────────────────────────────────────┐
│                  HARDWARE CONNECTIONS                       │
├─────────────────────────────────────────────────────────────┤
│                                                             │
│   POTENTIOMETER                                             │
│   ┌─────────┐                                               │
│   │   POT   │ ───────► ADC Channel 0                        │
│   │  0-3.3V │          (P7_0 or as configured)              │
│   └─────────┘          Returns: 0-100%                      │
│                                                             │
│   LED3 (Blue)                                               │
│   ┌─────────┐                                               │
│   │   LED   │ ◄─────── PWM Output                           │
│   │  BLUE   │          P16_5 (PWM capable)                  │
│   └─────────┘          Accepts: 0-100% brightness           │
│                                                             │
└─────────────────────────────────────────────────────────────┘

2.2 Hardware API

/* ADC - Potentiometer */
#include "aic-eec/sensors.h"

uint8_t pot_value = aic_adc_read_percent(AIC_ADC_CH0);  // Returns 0-100

/* PWM - LED Control */
#include "aic-eec/gpio.h"

aic_gpio_pwm_init(AIC_LED_BLUE);
aic_gpio_pwm_set_brightness(AIC_LED_BLUE, brightness);  // 0-100%

---

3. Code Architecture

3.1 Key Constants

/* Hardware Scope Parameters */
#define HW_SCOPE_WIDTH         410
#define HW_SCOPE_HEIGHT        210
#define HW_CHART_POINTS        200
#define HW_FFT_SIZE            256
#define HW_FFT_BINS            (HW_FFT_SIZE / 2)

/* Frequency Ranges */
#define HW_MIN_FREQUENCY       100     /* Scope min: 100 Hz */
#define HW_MAX_FREQUENCY       5000    /* Scope max: 5 kHz */
#define HW_GEN_MIN_FREQ        10      /* Gen min: 10 Hz (visible) */
#define HW_GEN_MAX_FREQ        500     /* Gen max: 500 Hz */

/* Duty Cycle Range */
#define HW_MIN_DUTY            10      /* Minimum 10% */
#define HW_MAX_DUTY            90      /* Maximum 90% */

/* Timer Update Rate */
#define HW_TIMER_PERIOD_MS     30      /* ~33 FPS */

3.2 State Variables

/* Panel Navigation */
static uint8_t hw_active_panel = 0;    /* 0=Scope, 1=Gen, 2=FFT */

/* Scope Panel State */
static uint32_t hw_frequency = 1000;   /* Current frequency */
static aic_wave_type_t hw_wave_type = AIC_WAVE_SINE;
static bool hw_scope_running = true;

/* Generator Panel State */
static uint32_t hw_gen_freq = 100;     /* Generator frequency */
static uint8_t hw_duty = 50;           /* Duty cycle 10-90% */
static bool hw_gen_output_enabled = false;

/* LED Output Phase Accumulator */
static uint32_t hw_led_phase = 0;
static uint32_t hw_led_phase_inc = 0;

3.3 POTEN-to-Parameter Mapping

static void hw_timer_cb(lv_timer_t *timer)
{
    /* Read POTEN value (0-100%) */
    uint8_t pot_percent = aic_adc_read_percent(AIC_ADC_CH0);

    if (hw_active_panel == 0) {
        /*=== SCOPE PANEL: POTEN → FREQUENCY ===*/
        uint32_t freq_range = HW_MAX_FREQUENCY - HW_MIN_FREQUENCY;
        hw_frequency = HW_MIN_FREQUENCY + (pot_percent * freq_range / 100);

        /* Update frequency label */
        lv_label_set_text_fmt(hw_freq_label, "Freq: %u Hz",
                              (unsigned int)hw_frequency);

        /* Generate and display waveform */
        aic_scope_generate_wave(hw_wave_type, hw_scope_buffer,
                                HW_CHART_POINTS, hw_frequency, 50);
        /* Update chart... */
    }
    else if (hw_active_panel == 1) {
        /*=== GEN PANEL: POTEN → DUTY CYCLE ===*/
        hw_duty = HW_MIN_DUTY + (pot_percent * (HW_MAX_DUTY - HW_MIN_DUTY) / 100);

        /* Sync slider with POTEN value */
        lv_slider_set_value(hw_gen_duty_slider, hw_duty, LV_ANIM_OFF);

        /* Update duty label */
        lv_label_set_text_fmt(hw_gen_duty_label, "Duty: %d%%", hw_duty);

        /* Update LED output */
        hw_update_led_output();
    }
}

3.4 Waveform-to-LED Conversion (Phase Accumulator)

/* Called in timer callback when OUTPUT is enabled */
static void hw_update_led_output(void)
{
    if (!hw_gen_output_enabled) {
        aic_gpio_pwm_set_brightness(AIC_LED_BLUE, 0);
        return;
    }

    /* Phase accumulator (0 to 65535 = one cycle) */
    hw_led_phase += hw_led_phase_inc;
    if (hw_led_phase >= 65536) {
        hw_led_phase -= 65536;
    }

    uint8_t brightness = 0;

    switch (hw_gen_wave_type) {
        case AIC_WAVE_SQUARE:
            /* Square wave: ON/OFF based on duty cycle */
            if ((hw_led_phase * 100 / 65536) < hw_duty) {
                brightness = 100;  /* ON */
            } else {
                brightness = 0;    /* OFF */
            }
            break;

        case AIC_WAVE_SINE:
            /* Sine wave: smooth brightness 0-100% */
            {
                float angle = (float)hw_led_phase * 2.0f * 3.14159f / 65536.0f;
                float sine_val = (sinf(angle) + 1.0f) / 2.0f;  /* 0 to 1 */
                brightness = (uint8_t)(sine_val * 100.0f);
            }
            break;

        case AIC_WAVE_TRIANGLE:
            /* Triangle wave: linear up/down */
            if (hw_led_phase < 32768) {
                brightness = (uint8_t)(hw_led_phase * 100 / 32768);
            } else {
                brightness = (uint8_t)((65536 - hw_led_phase) * 100 / 32768);
            }
            break;

        case AIC_WAVE_SAWTOOTH:
            /* Sawtooth: linear ramp */
            brightness = (uint8_t)(hw_led_phase * 100 / 65536);
            break;

        default:
            brightness = 0;
            break;
    }

    aic_gpio_pwm_set_brightness(AIC_LED_BLUE, brightness);
}