void setup() {  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}


tiny-tapeout-poc-new-internal-pulls.ino

Extra Credit: 4-bit Full-Adder with Carry

Note: Adding two n-bit numbers can result in n+1 bits.

In other words, the output requires an extra bit to account for a carry.

diagram.json

Digital Input

input-8-pins.chip.json

Digital Output

output-8-pins.chip.json

// Wokwi Custom Chip - For information and examples see:
// https://link.wokwi.com/custom-chips-alpha
//
// SPDX-License-Identifier: MIT
// Copyright (C) 2022 Uri Shaked / wokwi.com

#include "wokwi-api.h"
#include <stdio.h>
#include <stdlib.h>

typedef struct {
  pin_t ins[8];
  pin_t outs[8];
} chip_state_t;

void update_pins(chip_state_t *chip) {
  for (int i = 0; i < 8; i++) {
    pin_write(chip->outs[i], pin_read(chip->ins[i]));
  }
}

static void chip_pin_change(void *user_data, pin_t pin, uint32_t value) {
  update_pins((chip_state_t*)user_data);
}

void chip_init() {
  chip_state_t *chip = malloc(sizeof(chip_state_t));

  chip->ins[0] = pin_init("EXTIN0", INPUT_PULLDOWN);
  chip->ins[1] = pin_init("EXTIN1", INPUT_PULLDOWN);
  chip->ins[2] = pin_init("EXTIN2", INPUT_PULLDOWN);
  chip->ins[3] = pin_init("EXTIN3", INPUT_PULLDOWN);
  chip->ins[4] = pin_init("EXTIN4", INPUT_PULLDOWN);
  chip->ins[5] = pin_init("EXTIN5", INPUT_PULLDOWN);
  chip->ins[6] = pin_init("EXTIN6", INPUT_PULLDOWN);
  chip->ins[7] = pin_init("EXTIN7", INPUT_PULLDOWN);
  
  chip->outs[0] = pin_init("IN0", OUTPUT);
  chip->outs[1] = pin_init("IN1", OUTPUT);
  chip->outs[2] = pin_init("IN2", OUTPUT);
  chip->outs[3] = pin_init("IN3", OUTPUT);
  chip->outs[4] = pin_init("IN4", OUTPUT);
  chip->outs[5] = pin_init("IN5", OUTPUT);
  chip->outs[6] = pin_init("IN6", OUTPUT);
  chip->outs[7] = pin_init("IN7", OUTPUT);

  update_pins(chip);

  pin_watch_config_t watch_config = {
    .edge = BOTH,
    .pin_change = chip_pin_change,
    .user_data = chip,
  };
  for (int i = 0; i < 8; i++) {
    pin_watch(chip->ins[i], &watch_config);
  }
  
  // The following message will appear in the browser's DevTools console:
  printf("Hello from input 8 pins!\n");
}



input-8-pins.chip.c

// Wokwi Custom Chip - For information and examples see:
// https://link.wokwi.com/custom-chips-alpha
//
// SPDX-License-Identifier: MIT
// Copyright (C) 2022 Uri Shaked / wokwi.com

#include "wokwi-api.h"
#include <stdio.h>
#include <stdlib.h>

typedef struct {
  pin_t ins[8];
  pin_t outs[8];
} chip_state_t;

void update_pins(chip_state_t *chip) {
  for (int i = 0; i < 8; i++) {
    pin_write(chip->outs[i], pin_read(chip->ins[i]));
  }
}

static void chip_pin_change(void *user_data, pin_t pin, uint32_t value) {
  update_pins((chip_state_t*)user_data);
}

void chip_init() {
  chip_state_t *chip = malloc(sizeof(chip_state_t));

  chip->ins[0] = pin_init("OUT0", INPUT);
  chip->ins[1] = pin_init("OUT1", INPUT);
  chip->ins[2] = pin_init("OUT2", INPUT);
  chip->ins[3] = pin_init("OUT3", INPUT);
  chip->ins[4] = pin_init("OUT4", INPUT);
  chip->ins[5] = pin_init("OUT5", INPUT);
  chip->ins[6] = pin_init("OUT6", INPUT);
  chip->ins[7] = pin_init("OUT7", INPUT);
  
  chip->outs[0] = pin_init("EXTOUT0", OUTPUT);
  chip->outs[1] = pin_init("EXTOUT1", OUTPUT);
  chip->outs[2] = pin_init("EXTOUT2", OUTPUT);
  chip->outs[3] = pin_init("EXTOUT3", OUTPUT);
  chip->outs[4] = pin_init("EXTOUT4", OUTPUT);
  chip->outs[5] = pin_init("EXTOUT5", OUTPUT);
  chip->outs[6] = pin_init("EXTOUT6", OUTPUT);
  chip->outs[7] = pin_init("EXTOUT7", OUTPUT);

  update_pins(chip);

  pin_watch_config_t watch_config = {
    .edge = BOTH,
    .pin_change = chip_pin_change,
    .user_data = chip,
  };
  for (int i = 0; i < 8; i++) {
    pin_watch(chip->ins[i], &watch_config);
  }
  
  // The following message will appear in the browser's DevTools console:
  printf("Hello from output 8 pins!\n");
}



output-8-pins.chip.c

[Tiny Tapeout Puzzles](https://tinytapeout.com/digital_design/puzzle_adder/)

Why are adders important? Lots of basic computation and math is dependent on addition and multiplication, making adders a crucial circuit for computers. And while doing basic arithmetic may seem to be a solved problem, there is actually lots of [ongoing research on how to optimize adders](https://www.zerotoasiccourse.com/post/interview-with-teo/). When so many of a computer's instructions rely on addition, even tiny improvements can make a big difference!

This design implements the extra-credit 4-bit full-adder with carry.

