AVR Freaks

Go on.  You are mixing up uint8_t and uint16_t.

#include <avr/io.h>
#include <avr/eeprom.h>

int main(void) {
    uint16_t data=0;

    for (uint16_t i=0; i<1024; i++) { // erase all 1024 bytes
        eeprom_write_byte((uint16_t *) i, 0xff);
    }

    for (uint16_t i=0; i<512; i+=0x20) { // 0x0000, 0x0011, 0x0022, ..., 0x00FF
        eeprom_write_word((uint16_t *) i, data); // at byte locations 0x0000, 0x0020, 0x0040, ..., 0x01E0
        data += 0x11;                    // byte locations 0x0200 - 0x03FF are untouched
    }

    for (uint16_t i=0; i<512; i+=0x20) {
        data = eeprom_read_word((uint16_t *) i); // should read 0x0000, 0x0011, 0x0022, ..., 0x00FF
    }

    return(0);
}

Untested.  But you should be able to view in the Simulator.

When you wrote

    for (uint16_t i=0; i<1024; i++) { // erase all 1024 bytes
        eeprom_write_word((uint16_t *) i, 0x00ff);
    }

You would effectively write 0xFF in each byte except for 0x00 in location 0x0000 where it has wrapped round.

i.e. you get almost what you intended but in the wrong way.

Untested.   I will let you try it for yourself.

Ah-ha.  I just looked at your hex dump.   How did you get that ?

The AS7.0 Simulator produces everything as expected.   (note that words are stored little-endian)

David.

p.s. I might try your program out on a real-life ATmega328P

Are you concerned about avrdude or just ArduinoISP ?

I can't believe that avrdude has a problem with reading the EEPROM.

After all,  avrdude has been in use for many years.

I guess that ArduinoISP users seldom do more than a Blinky.   And if they do it seldom contains EEPROM.

ArduinoISP.ino source code comes with every Arduino installation.

It looks ok.  But I will not bother trying it until you confirm your concerns.

Of course avrdude has recently undergone "changes".

David.

Most conf files have:   (I am looking at historic Arduino conf files)

    memory "eeprom"
    paged        = no;
    page_size    = 4;
    size        = 1024;

So I suspect you just need to remove the num_pages entry.

David.