For my Apple ][ projects, I needed an EEPROM programmer. After Googling a while, I found one DIY project on 6502.org. It is the MEEPROMMER, by Mario Keller.
My build, the empty socket is for the EEPROM
A few nights searching for parts and soldering, I had one built and I added my Arduino Pro micro (5V/16MHz). It all seemed working fine until I tried to write my first bytes. The commandline tool I found (by Zack Nelson, with some tweaks by Paul Annesley), written in Python didn’t receive the ‘%’ prompt when writing more than $180 (384) bytes. After searching the internet (and various forums), I got some reply from someone, who said that maybe the Pro micro was/is the culprit. He tested a test sketch, which failed with the Pro micro, and ran it on his Arduino UNO. This worked for him.
Pro micro removed, UNO attached through jumper wires
I asked my uncle if he could lend me one of his UNO boards. I uploaded an unmodified sketch and ran the python script by Paul. With success I can now write an EEPROM (I use the AT28C64B for my project).
As a reference I will mention the source(s) of the Arduino sketch and python script below, with which I had success:
Arduino Sketch (original here)
/**
* ** project Arduino EEPROM programmer **
*
* This sketch can be used to read and write data to a
* AT28C64 or AT28C256 parallel EEPROM
*
* $Author: mario, edited by Zack $
* $Date: 2013/05/05 11:01:54 $
* $Revision: 1.3 $
*
* This software is freeware and can be modified, reused or thrown away without any restrictions.
*
* Use this code at your own risk. I'm not responsible for any bad effect or damages caused by this software!!!
*
**/
#define VERSIONSTRING "MEEPROMMER $Revision: 1.3 $ $Date: 12/18/2013 15:56:00 $, CMD:R,r,w,W,V, u"
// shiftOut part
#define PORTC_DS 0
#define PORTC_LATCH 1
#define PORTC_CLOCK 2
// eeprom IO lines:D0-D7 = pins2-9
// IO lines for the eeprom control
#define PORTC_CE 3
#define PORTC_OE 4
#define PORTC_WE 5
//a buffer for bytes to burn
#define BUFFERSIZE 1024
byte buffer[BUFFERSIZE];
//command buffer for parsing commands
#define COMMANDSIZE 16
char cmdbuf[COMMANDSIZE];
unsigned int startAddress,endAddress;
unsigned int lineLength,dataLength;
//define COMMANDS
#define NOCOMMAND 0
#define VERSION 1
#define READ_HEX 10
#define READ_BIN 11
#define WRITE_PAGE 20
#define WRITE_BIN 21
#define UNLOCK 30
/*****************************************************************
*
* CONTROL and DATA functions
*
****************************************************************/
void data_bus_input(){
DDRD &= 0b00000011;
DDRB &= 0b11111100;
}
void data_bus_output(){
DDRD |= 0b11111100;
DDRB |= 0b00000011;
}
byte read_data_bus(){
return ((PINB<<6)|(PIND>>2));
}
void write_data_bus(byte data){
PORTB &= 0b11111100;
PORTB |= (data>>6);
PORTD &= 0b00000011;
PORTD |= (data<<2);
}
//shift out the given address to the 74hc595 registers
void set_address_bus(unsigned int address){
bitClear(PORTC,PORTC_LATCH); //disable latch line
fastShiftOut(highByte(address)); //shift out highbyte
fastShiftOut(lowByte(address)); //shift out lowbyte
bitSet(PORTC,PORTC_LATCH); //enable latch and set address
}
void fastShiftOut(byte data){
for(int i=7; i>=0; i--){//shift MSB first
//clear data pin after shift to prevent bleed through
bitClear(PORTC,PORTC_DS);
bitClear(PORTC,PORTC_CLOCK);
if(bitRead(data,i))bitSet(PORTC,PORTC_DS);
//register shifts bits on rising clock
bitSet(PORTC,PORTC_CLOCK);
}
bitClear(PORTC,PORTC_CLOCK);
}
byte read_byte(unsigned int address){
data_bus_input(); //set databus for reading
bitClear(PORTC,PORTC_CE); //enable chip select
bitSet(PORTC,PORTC_WE); //disable write
set_address_bus(address); //set address bus
bitClear(PORTC,PORTC_OE); //enable output
//delay 312.5ns @ 16MHz
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
byte data = read_data_bus();
bitSet(PORTC,PORTC_OE); //disable output
bitSet(PORTC,PORTC_CE); //enable chip select
return data;
}
void fast_write(unsigned int address, byte data){
bitSet(PORTC,PORTC_OE); //first disable output
bitSet(PORTC,PORTC_WE); //disable write
set_address_bus(address); //set address bus
data_bus_output(); //set databus to output
write_data_bus(data); //set data bus
bitClear(PORTC,PORTC_CE); //enable chip select
bitClear(PORTC,PORTC_WE); //enable write
__asm__("nop\n\t""nop\n\t"); //delay 125ns @ 16MHz
bitSet(PORTC,PORTC_WE); //disable write
data_bus_input();
bitClear(PORTC,PORTC_OE);
//delay 312.5ns @ 16MHz
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
while(data != read_data_bus()); //poll data
bitSet(PORTC,PORTC_OE);
bitSet(PORTC,PORTC_CE);
}
void write_block_page(unsigned int address, byte* buffer, int len, int page){
address &= ~(page-1); //address must not break page boundaries
bitSet(PORTC,PORTC_WE); //disable write
bitClear(PORTC,PORTC_CE); //enable chip
for(int n=0; n<len/page; n++){
bitSet(PORTC,PORTC_OE);
data_bus_output(); //set databus to output
for(unsigned int i=n*page; i<(n+1)*page; i++){
bitSet(PORTC,PORTC_WE); //disable write
set_address_bus(address+i); //set address bus
write_data_bus(buffer[i]); //set data bus
bitClear(PORTC,PORTC_WE); //enable write
//100ns+ tWP delay caused by for looping
}
bitSet(PORTC,PORTC_WE); //write must be high for tBLC(100us)
data_bus_input();
bitClear(PORTC,PORTC_OE); //enable output
//delay 312.5ns @ 16MHz
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
while(buffer[(n+1)*page-1] != read_data_bus()); //poll data
}
bitSet(PORTC,PORTC_CE);
}
/************************************************
*
* COMMAND and PARSING functions
*
*************************************************/
void readCommand(){
int idx = 0;
do {//read 'til linebreak or buffer is full
if(Serial.available())cmdbuf[idx++] = Serial.read();
} while (cmdbuf[idx-1] != '\n' && idx < COMMANDSIZE);
for(;idx<COMMANDSIZE;idx++)cmdbuf[idx] = 0;//clear the rest of command buffer
}
byte parseCommand(){
//command format:C AAAA DDDD LL
startAddress=hexWord(cmdbuf+2); //A
dataLength=hexWord(cmdbuf+7); //D
lineLength=hexByte(cmdbuf+12); //L
switch(cmdbuf[0]){
case 'R':
return(READ_HEX);
case 'r':
return(READ_BIN);
case 'W':
return(WRITE_PAGE);
case 'w':
return(WRITE_BIN);
case 'V':
return(VERSION);
case 'u':
return(UNLOCK);
default:
return(NOCOMMAND);
}
}
byte hexDigit(char c){ //ascii char to value
if(c >= '0' && c <= '9')return c - '0';
if(c >= 'a' && c <= 'f')return c - 'a' + 10;
if(c >= 'A' && c <= 'F')return c - 'A' + 10;
return 0;// getting here is bad: it means the character was invalid
}
byte hexByte(char* a){ //ascii byte to value
return ((hexDigit(a[0])<<4) | hexDigit(a[1]));
}
//ascii word to value
unsigned int hexWord(char* data){
return ((hexDigit(data[0])<<12)|
(hexDigit(data[1])<<8)|
(hexDigit(data[2])<<4)|
(hexDigit(data[3])));
}
/************************************************
*
* INPUT / OUTPUT Functions
*
*************************************************/
void read_block(unsigned int from, unsigned int to, int linelength){
int outcount = 0;
//loop from "from address" to "to address" (included)
for(unsigned int address = from; address <= to; address++){
if(outcount == 0){
//print out the address at the beginning of the line
Serial.println();
Serial.print("0x");
printAddress(address);
Serial.print(" : ");
}
//print data, separated by a space
printByte(read_byte(address));
Serial.print(" ");
outcount = (++outcount % linelength);
}
Serial.println();
}
void read_binblock(unsigned int from, unsigned int to){
for(unsigned int address = from; address <= to; address++){
Serial.write(read_byte(address));
}
Serial.print('\0');//success return code
}
void write_block(unsigned int address, byte* buffer, int len){
for(unsigned int i = 0; i < len; i++){
fast_write(address+i,buffer[i]);
}
}
void printAddress(unsigned int address){
if(!(address & 0xfff0)) Serial.print("0");
if(!(address & 0xff00)) Serial.print("0");
if(!(address & 0xf000)) Serial.print("0");
Serial.print(address, HEX);
}
void printByte(byte data){
if(!(data & 0xf0)) Serial.print("0");
Serial.print(data, HEX);
}
/************************************************
*
* MAIN
*
*************************************************/
void setup(){
DDRC = 0b00111111; //set EEPROM & shiftOut Pins as output
PORTC = 0b00111000; //set EEPROM Pins high
//Serial.begin(57600); //set speed of serial connection
Serial.begin(115200);
while(!Serial) {
// We might need this!
}
}
void loop(){
int bytes = 0;
readCommand();
switch(parseCommand()){
case READ_HEX:
if(lineLength==0) lineLength=32; //default
endAddress = startAddress + dataLength -1;
read_block(startAddress,endAddress,lineLength);
Serial.println('%');//success return code
break;
case READ_BIN:
endAddress = startAddress + dataLength -1;
read_binblock(startAddress,endAddress);
break;
case WRITE_PAGE:
if(dataLength > 1024) dataLength = 1024;
while(bytes < dataLength)if(Serial.available())buffer[bytes++] = Serial.read();
if(lineLength==0) lineLength=32; //page size
write_block_page(startAddress,buffer,dataLength,lineLength);
Serial.println('%');
break;
case WRITE_BIN:
if(dataLength > 1024) dataLength = 1024; //1024 is max
while(bytes < dataLength)if(Serial.available())buffer[bytes++] = Serial.read();
write_block(startAddress,buffer,dataLength);
Serial.println('%');
break;
case VERSION:
Serial.println(VERSIONSTRING);
break;
case UNLOCK:
fast_write(0x5555,0xAA);
fast_write(0x2AAA,0x55);
fast_write(0x5555,0x80);
fast_write(0x5555,0xAA);
fast_write(0x2AAA,0x55);
fast_write(0x5555,0x20);
Serial.print('%');//success return code
break;
}
}
Python script (original here)
#!/usr/bin/env python3
#Meeprommer commandline interface
#By Zack Nelson
#Project Home:
#https://github.com/mkeller0815/MEEPROMMER
#http://www.ichbinzustaendig.de/dev/meeprommer-en
# Some tweaks by @pda
import serial, sys, argparse
# Parse command line arguments
parser = argparse.ArgumentParser(
description='Meepromer Command Line Interface',
epilog='Read source for further information')
task = parser.add_mutually_exclusive_group()
task.add_argument('-V', '--version', dest="cmd", action="store_const",
const="version", help='Request and display device version')
task.add_argument('-w', '--write', dest="cmd", action="store_const",
const="write", help='Write to EEPROM')
task.add_argument('-W', '--write_paged', dest="cmd", action="store_const",
const="write_paged", help='Fast paged write to EEPROM')
task.add_argument('-r', '--read', dest="cmd", action="store_const",
const="read", help='Read from EEPROM as ascii')
task.add_argument('-d', '--dump', dest="cmd", action="store_const",
const="dump", help='Dump EEPROM to binary file')
task.add_argument('-v', '--verify', dest="cmd", action="store_const",
const="verify", help='Compare EEPROM with file')
task.add_argument('-u', '--unlock', dest="cmd", action="store_const",
const="unlock", help='Unlock EEPROM')
task.add_argument('-l', '--list', dest="cmd", action="store_const",
const="list", help='List serial ports')
parser.add_argument('-a', '--address', action='store', default='0',
help='Starting eeprom address (as hex), default 0')
parser.add_argument('-o', '--offset', action='store', default='0',
help='Input file offset (as hex), default 0')
parser.add_argument('-b', '--bytes', action='store', default='8',
type=int, help='Number of kBytes to r/w, default 8')
parser.add_argument('-p', '--page_size', action='store', default='32',
type=int, help='Number of bytes per EEPROM page e.g.:'+
'CAT28C*=32, AT28C*=64, X28C*=64, default 32')
parser.add_argument('-f', '--file', action='store',
help='Name of data file')
parser.add_argument('-c', '--com', action='store',
default='COM5', help='Com port address')
parser.add_argument('-s', '--speed', action='store',
type=int, default='115200', help='Com port baud, default 115200')
def list_ports():
from serial.tools import list_ports
for x in list_ports.comports():
print(x[0], x[1])
def dump_file():
ser.flushInput()
ser.write(bytes("r "+format(args.address,'04x')+" "+
format(args.address+args.bytes*1024,'04x')+
" 10\n", 'ascii'))
eeprom = ser.read(args.bytes*1024)
if(ser.read(1) != b'\0'):
print("Error: no Ack")
sys.exit(1)
try:
fo = open(args.file,'wb+')
except OSError:
print("Error: File cannot be opened, verify it is not in use")
sys.exit(1)
fo.write(eeprom)
fo.close()
def verify():
print("Verifying...")
ser.flushInput()
ser.write(bytes("r "+format(args.address,'04x')+" "+
format(args.bytes*1024,'04x')+" 10\n", 'ascii'))
try:
fi = open(args.file,'rb')
except FileNotFoundError:
print("Error: ",args.file," not found, please select a valid file")
sys.exit(1)
except TypeError:
print("Error: No file specified")
sys.exit(1)
fi.seek(args.offset)
file = fi.read(args.bytes*1024)
eeprom = ser.read(args.bytes*1024)
if ser.read(1) != b'\0':
print("Error: no EOF received")
if file != eeprom:
print("Not equal")
n = 0
for i in range(args.bytes*1024):
if file[i] != eeprom[i]:
n+=1
print(n,"differences found")
sys.exit(1)
else:
print("Ok")
def read_eeprom():
ser.flushInput()
ser.write(bytes("R "+format(args.address,'04x')+" "+
format(args.address+args.bytes*1024,'04x')+
" 10\n", 'ascii'))
ser.readline()#remove blank starting line
for i in range(round(args.bytes*1024/16)):
print(ser.readline().decode('ascii').rstrip())
def write_eeprom(paged):
import time
fi = open(args.file,'rb')
fi.seek(args.offset)
now = time.time() #start our stopwatch
for i in range(args.bytes): #write n blocks of 1024 bytes
output = fi.read(1024)
print("Writing from",format(args.address+i*1024,'04x'),
"to",format(args.address+i*1024+1023,'04x'))
if paged:
ser.write(bytes("W "+format(args.address+i*1024,'04x')+
" 0400 "+format(args.page_size,'02x')+"\n", 'ascii'))
else:
ser.write(bytes("w "+format(args.address+i*1024,'04x')+
" 0400 00\n", 'ascii'))
ser.flushInput()
ser.write(output)
if(ser.read(1) != b'%'):
print("Error: no Ack")
sys.exit(1)
print("Wrote",args.bytes*1024,"bytes in","%.2f"%(time.time()-now),"seconds")
def unlock():
print("Unlocking...")
ser.flushInput()
ser.write(bytes("u 0000 0000 00\n", 'ascii'))
if ser.read(1) != b'%':
print("Error: no ack")
sys.exit(1)
def version():
ser.write(b'V\n')
print(ser.readline().decode('ascii').rstrip())
args = parser.parse_args()
#convert our hex strings to ints
args.address = int(args.address,16)
args.offset = int(args.offset,16)
class DebugSerial(serial.Serial):
def write(self, data):
#print("write: %s" % (data,))
super().write(data)
SERIAL_TIMEOUT = 20 #seconds
try:
ser = DebugSerial(args.com, args.speed, timeout=SERIAL_TIMEOUT)
except serial.serialutil.SerialException:
print("Error: Serial port is not valid, please select a valid port")
sys.exit(1)
# It seems necessary to wait >= ~1.8 seconds for the device to respond.
import time
time.sleep(2)
if args.cmd == 'version':
version()
elif args.cmd == 'write':
write_eeprom(False)
elif args.cmd == 'write_paged':
write_eeprom(True)
elif args.cmd == 'read':
read_eeprom()
elif args.cmd == 'dump':
dump_file()
elif args.cmd == 'verify':
verify()
elif args.cmd == 'unlock':
unlock();
elif args.cmd == 'list':
list_ports()
ser.close()
sys.exit(0)