Arduino 23LC1024 SRAM object

sram_23lc1024.cpp

#pragma once
#include <Arduino.h>
#include <SPI.h>

// 23lc1024 pin mapping
//
// 1  CS
// 2  MISO
// 3  (tie gnd)
// 4  GND
// 5  MOSI
// 6  SCK
// 7  (tie vcc)
// 8  VCC

struct sram_23lc1024_t {

  sram_23lc1024_t(SPIClass &spi, uint8_t cs)
    : spi(spi)
    , cs(cs)
  {}

  void write(uint32_t addr, uint8_t data) {
    digitalWrite(cs, LOW);
    spi.beginTransaction(
      CS_PIN_CONTROLLED_BY_USER,
      SPISettings{SPI_SPEED_CLOCK_DEFAULT, MSBFIRST, SPI_MODE0});
    // write command
    spi.transfer(WRITE);
    // address
    spi.transfer((addr >> 16) & 0xff);
    spi.transfer((addr >> 8 ) & 0xff);
    spi.transfer((addr      ) & 0xff);
    // data
    spi.transfer(data);
    spi.endTransaction();
    digitalWrite(cs, HIGH);
  }

  uint8_t read(uint32_t addr) {
    digitalWrite(cs, LOW);
    uint8_t out = 0;
    spi.beginTransaction(
      CS_PIN_CONTROLLED_BY_USER,
      SPISettings{SPI_SPEED_CLOCK_DEFAULT, MSBFIRST, SPI_MODE0});
    // read command
    spi.transfer(READ);
    // address
    spi.transfer((addr >> 16) & 0xff);
    spi.transfer((addr >> 8 ) & 0xff);
    spi.transfer((addr      ) & 0xff);
    // data
    out = spi.transfer(0);
    spi.endTransaction();
    digitalWrite(cs, HIGH);
    return out;
  }

protected:

  enum {
    WRITE = 0x02,
    READ = 0x03,
  };

  SPIClass &spi;
  const uint8_t cs;
};