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#define SHIFT_DATA 2
#define SHIFT_CLK 3
#define SHIFT_LATCH 4
#define EEPROM_D0 5
#define EEPROM_D7 12
#define WRITE_EN 13
/*
* Output the address bits and outputEnable signal using shift registers.
*/
void setAddress(int address, bool outputEnable) {
shiftOut(SHIFT_DATA, SHIFT_CLK, MSBFIRST, (address >> 8) | (outputEnable ? 0x00 : 0x80));
shiftOut(SHIFT_DATA, SHIFT_CLK, MSBFIRST, address);
digitalWrite(SHIFT_LATCH, LOW);
digitalWrite(SHIFT_LATCH, HIGH);
digitalWrite(SHIFT_LATCH, LOW);
}
/*
* Read a byte from the EEPROM at the specified address.
*/
byte readEEPROM(int address) {
for (int pin = EEPROM_D0; pin <= EEPROM_D7; pin += 1) {
pinMode(pin, INPUT);
}
setAddress(address, /*outputEnable*/ true);
byte data = 0;
for (int pin = EEPROM_D7; pin >= EEPROM_D0; pin -= 1) {
data = (data << 1) + digitalRead(pin);
}
return data;
}
/*
* Write a byte to the EEPROM at the specified address.
*/
void writeEEPROM(int address, byte data) {
setAddress(address, /*outputEnable*/ false);
for (int pin = EEPROM_D0; pin <= EEPROM_D7; pin += 1) {
pinMode(pin, OUTPUT);
}
for (int pin = EEPROM_D0; pin <= EEPROM_D7; pin += 1) {
digitalWrite(pin, data & 1);
data = data >> 1;
}
digitalWrite(WRITE_EN, LOW);
delayMicroseconds(1);
digitalWrite(WRITE_EN, HIGH);
delay(10);
}
/*
* Read the contents of the EEPROM and print them to the serial monitor.
*/
void printContents() {
for (int base = 0; base <= 255; base += 16) {
byte data[16];
for (int offset = 0; offset <= 15; offset += 1) {
data[offset] = readEEPROM(base + offset);
}
char buf[80];
sprintf(buf, "%03x: %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
base, data[0], data[1], data[2], data[3], data[4], data[5], data[6], data[7],
data[8], data[9], data[10], data[11], data[12], data[13], data[14], data[15]);
Serial.println(buf);
}
}
// 4-bit hex decoder for common anode 7-segment display
byte data[] = { 0x81, 0xcf, 0x92, 0x86, 0xcc, 0xa4, 0xa0, 0x8f, 0x80, 0x84, 0x88, 0xe0, 0xb1, 0xc2, 0xb0, 0xb8 };
// 4-bit hex decoder for common cathode 7-segment display
// byte data[] = { 0x7e, 0x30, 0x6d, 0x79, 0x33, 0x5b, 0x5f, 0x70, 0x7f, 0x7b, 0x77, 0x1f, 0x4e, 0x3d, 0x4f, 0x47 };
void setup() {
// put your setup code here, to run once:
pinMode(SHIFT_DATA, OUTPUT);
pinMode(SHIFT_CLK, OUTPUT);
pinMode(SHIFT_LATCH, OUTPUT);
digitalWrite(WRITE_EN, HIGH);
pinMode(WRITE_EN, OUTPUT);
Serial.begin(57600);
// Erase entire EEPROM
Serial.print("Erasing EEPROM");
for (int address = 0; address <= 2047; address += 1) {
writeEEPROM(address, 0xff);
if (address % 64 == 0) {
Serial.print(".");
}
}
Serial.println(" done");
// Program data bytes
Serial.print("Programming EEPROM");
for (int address = 0; address < sizeof(data); address += 1) {
writeEEPROM(address, data[address]);
if (address % 64 == 0) {
Serial.print(".");
}
}
Serial.println(" done");
// Read and print out the contents of the EERPROM
Serial.println("Reading EEPROM");
printContents();
}
void loop() {
// put your main code here, to run repeatedly:
}
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