#include <SPI.h>

const int loadPin = 5; // Connect to MAX6921 LOAD
const int blankPin = 19; // Connect to MAX6921 LOAD
const int clkPin  = 18; // Your chosen Clock pin
const int dataPin = 23; // Your chosen Data (MOSI) pin
const int noPin = -1;

#include <Arduino.h>
// ESP32 GPIO pins
#define PIN_DIN   23
#define PIN_CLK   22
#define PIN_LOAD  18
#define PIN_BLANK 5
// MAX6921: 20 outputs
// OUT0–7 = segments A–DP
// OUT8–16 = GRID1–9

const int NUM_DIGITS = 9;
const int NUM_SEGMENTS = 8;  // A,B,C,D,E,F,G,DP
// Segment patterns: bit = segment A–DP
// For walking each segment one at a time
uint32_t segmentMask[NUM_SEGMENTS] = {
  1UL << 9, // Segment A
  1UL << 8, // Segment B
  1UL << 7, // Segment C
  1UL << 6, // Segment D
  1UL << 5, // Segment E
  1UL << 4, // Segment F
  1UL << 3, // Segment G
  1UL << 2  // Segment DP
};

uint32_t gridMask[NUM_DIGITS] = {
  1UL << 19, // Grid 1
  1UL << 18, // Grid 2
  1UL << 17, // Grid 3
  1UL << 16, // Grid 4
  1UL << 15, // Grid 5
  1UL << 14, // Grid 6
  1UL << 13, // Grid 7
  1UL << 12, // Grid 8
  1UL << 11  // Grid 9
};


void setup() {
  pinMode(PIN_DIN, OUTPUT);
  pinMode(PIN_CLK, OUTPUT);
  pinMode(PIN_LOAD, OUTPUT);
  pinMode(PIN_BLANK, OUTPUT);

  digitalWrite(PIN_LOAD, LOW);
  digitalWrite(PIN_CLK, LOW);
  digitalWrite(PIN_DIN, LOW);
  digitalWrite(PIN_BLANK, LOW);
}
// Shift out 20 bits (MSB first)
void shiftOut20(uint32_t value) {
  for (int i = 19; i >= 0; i--) {
    digitalWrite(PIN_CLK, LOW);
    digitalWrite(PIN_DIN, (value & (1UL << i)) ? HIGH : LOW);
    digitalWrite(PIN_CLK, HIGH);
  }
}

void loop() {
  // Walk all digits & segments
  for (int d = 0; d < NUM_DIGITS; d++) {
    for (int s = 0; s < NUM_SEGMENTS; s++) {
      uint32_t val = gridMask[d] | segmentMask[s];
      digitalWrite(PIN_BLANK, HIGH);
      digitalWrite(PIN_LOAD, LOW);
      shiftOut20(val);
      digitalWrite(PIN_LOAD, HIGH);  // latch
      digitalWrite(PIN_BLANK, LOW);
      delay(20);                    // 5 Hz
    }
  }
}