# include <SPI.h>

# define CS1
# define CS2 

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32-S3!");
}


void loop() {
  // put your main code here, to run repeatedly:
  delay(10); // this speeds up the simulation
}


sketch.ino

diagram.json

bmi270

bmi270.chip.json

// Wokwi Custom Chip - For docs and examples see:
// https://docs.wokwi.com/chips-api/getting-started
//
// SPDX-License-Identifier: MIT
// Copyright 2023 Phickies

#include "wokwi-api.h"
#include <stdio.h>
#include <stdlib.h>

typedef struct {
  pin_t cs_pin;
  uint32_t spi;
  uint8_t spi_buffer[1];
} chip_state_t;

static void chip_pin_change(void *user_data, pin_t pin, uint32_t value);
static void chip_spi_done(void *user_data, uint8_t *buffer, uint32_t count);

void chip_init() {
  chip_state_t *chip = malloc(sizeof(chip_state_t));

  chip->cs_pin = pin_init("CSB", INPUT_PULLUP);

  const pin_watch_config_t watch_config = {
    .edge = BOTH,
    .pin_change = chip_pin_change,
    .user_data = chip,
  };
  pin_watch(chip->cs_pin, &watch_config);

  const spi_config_t spi_config = {
    .sck = pin_init("SCX", INPUT),
    .miso = pin_init("SDO", INPUT),
    .mosi = pin_init("SDX", INPUT),
    .done = chip_spi_done,
    .user_data = chip,
  };
  chip->spi = spi_init(&spi_config);

  printf("BMI270 SPI interface initialized!\n");

}

uint8_t rot13(uint8_t value) {
  const uint8_t ROT = 13;
  if(value >= 'A' && value <='Z') {
    return (value + ROT) <= 'Z' ? value + ROT : value - ROT;
  }
  if(value >= 'a' && value <= 'z') {
    return (value + ROT) <= 'z' ? value + ROT : value - ROT;
  }
  return value;
}

void chip_pin_change(void *user_data, pin_t pin, uint32_t value) {
  chip_state_t *chip = (chip_state_t*)user_data;
  // Handle CS pin logic
  if (pin == chip->cs_pin) {
    if (value == LOW) {
      printf("SPI chip selected\n");
      chip->spi_buffer[0] = ' '; // Some dummy data for the first character
      spi_start(chip->spi, chip->spi_buffer, sizeof(chip->spi_buffer));
    } else {
      printf("SPI chip deselected\n");
      spi_stop(chip->spi);
    }
  }
}

void chip_spi_done(void *user_data, uint8_t *buffer, uint32_t count) {
  chip_state_t *chip = (chip_state_t*)user_data;
  if (!count) {
    // This means that we got here from spi_stop, and no data was received
    return;
  }

  // Apply the ROT13 transformation, and store the result in the buffer.
  // The result will be read back during the next SPI transfer.
  buffer[0] = rot13(buffer[0]);

  if (pin_read(chip->cs_pin) == LOW) {
    // Continue with the next character
    spi_start(chip->spi, chip->spi_buffer, sizeof(chip->spi_buffer));
  }
}