// VersaPad v2 – SAMD21G18A Custom Variant
// Pin descriptions and peripheral object definitions

#include "variant.h"
#include "Arduino.h"

// ─── g_APinDescription ────────────────────────────────────────────────────────
// Maps Arduino pin D0–D25 to SAMD21 port/pin pairs.
//
// Format:
//   { PORT, PIN, PinType, PinAttr, ADC_Channel, PWM_Channel, TC_Channel, ExtInt }
//
// ─────────────────────────────────────────────────────────────────────────────

const PinDescription g_APinDescription[] = {

    // ── Button Matrix: Columns (D0–D4) ────────────────────────────────────────
    // Driven LOW one at a time during scanning; idle = INPUT_PULLUP or OUTPUT HIGH

    // D0  – PA08 – COL_4
    { PORTA,  8, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NMI },
    // D1  – PA09 – COL_3
    { PORTA,  9, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_9  },
    // D2  – PA10 – COL_2
    { PORTA, 10, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_10 },
    // D3  – PA11 – COL_1
    { PORTA, 11, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_11 },
    // D4  – PB10 – COL_0  (also: encoder SW column)
    { PORTB, 10, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_10 },

    // ── Button Matrix: Rows (D5–D9) ───────────────────────────────────────────
    // Read as INPUT_PULLUP; go LOW when a button in the active column is pressed

    // D5  – PB11 – ROW_0
    { PORTB, 11, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_11 },
    // D6  – PA12 – ROW_1
    { PORTA, 12, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_12 },
    // D7  – PA13 – ROW_2
    { PORTA, 13, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_13 },
    // D8  – PA14 – ROW_3
    { PORTA, 14, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_14 },
    // D9  – PA15 – ROW_4
    { PORTA, 15, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_15 },

    // ── Rotary Encoders (D10–D17) ─────────────────────────────────────────────
    // All wired to EIC (External Interrupt Controller) via PMUX A.
    // Quadrature decoding done in ISRs.

    // D10 – PA16 – ENC3_A  EIC EXTINT[0]
    { PORTA, 16, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_0  },
    // D11 – PA17 – ENC3_B  EIC EXTINT[1]
    { PORTA, 17, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_1  },
    // D12 – PA18 – ENC2_A  EIC EXTINT[2]
    { PORTA, 18, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_2  },
    // D13 – PA19 – ENC2_B  EIC EXTINT[3]
    { PORTA, 19, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_3  },
    // D14 – PA20 – ENC1_A  EIC EXTINT[4]
    { PORTA, 20, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_4  },
    // D15 – PA21 – ENC1_B  EIC EXTINT[5]
    { PORTA, 21, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_5  },
    // D16 – PA22 – ENC0_A  EIC EXTINT[6]
    { PORTA, 22, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_6  },
    // D17 – PA23 – ENC0_B  EIC EXTINT[7]
    { PORTA, 23, PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_7  },

    // ── WS2812 SPI – SERCOM5 (D18–D20) ───────────────────────────────────────
    // PB22/PB23 use peripheral function D → PIO_SERCOM_ALT
    // PB03 uses peripheral function D → PIO_SERCOM_ALT

    // D18 – PB22 – SPI MOSI / WS2812 data  (SERCOM5 PAD[2])
    { PORTB, 22, PIO_SERCOM_ALT, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NONE },
    // D19 – PB23 – SPI SCK                 (SERCOM5 PAD[3])
    { PORTB, 23, PIO_SERCOM_ALT, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NONE },
    // D20 – PB03 – SPI MISO (unused)       (SERCOM5 PAD[1])
    { PORTB,  3, PIO_SERCOM_ALT, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NONE },

    // ── USB D– / D+ (D21–D22) ────────────────────────────────────────────────
    // D21 – PA24 – USB D–
    { PORTA, 24, PIO_COM, PIN_ATTR_NONE, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NONE },
    // D22 – PA25 – USB D+
    { PORTA, 25, PIO_COM, PIN_ATTR_NONE, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NONE },

    // ── Faders / ADC (D23–D25 = A0–A2) ──────────────────────────────────────
    // D23/A0 – PA02 – FADER_0  ADC AIN[0]
    { PORTA,  2, PIO_ANALOG, PIN_ATTR_ANALOG, ADC_Channel0, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NONE },
    // D24/A1 – PA03 – FADER_1  ADC AIN[1]  (also VREFA – do not use as digital)
    { PORTA,  3, PIO_ANALOG, PIN_ATTR_ANALOG, ADC_Channel1, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NONE },
    // D25/A2 – PB08 – FADER_2  ADC AIN[2]
    { PORTB,  8, PIO_ANALOG, PIN_ATTR_ANALOG, ADC_Channel2, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NMI  },
};

extern "C" {
    unsigned int PINCOUNT_fn() { return PINS_COUNT; }
}

// ─── USB ──────────────────────────────────────────────────────────────────────
void initVariant() {
    // Nothing board-specific needed at startup.
    // USB is handled by the Arduino SAMD core.
}