Weird PROGMEM issue with 2 dimensional array

Projects Programming
1

Evening gents, when I declare my array with PROGMEM it won't return the correct data but without PROGMEM it's fine

Here's the code:

const PROGMEM int DefaultFuelMapWidth = 8;
const PROGMEM int DefaultFuelMapHeight = 12;
const PROGMEM int DefaultFuelMap[DefaultFuelMapHeight][DefaultFuelMapWidth] =
{
  {850, 850, 850, 850, 850, 850, 850, 850},
  {780, 780, 780, 780, 780, 780, 780, 780},
  {780, 780, 830, 830, 830, 830, 830, 830},
  {780, 830, 830, 830, 830, 830, 830, 830},
  {830, 830, 830, 830, 830, 830, 830, 830},
  {830, 830, 830, 830, 830, 830, 830, 830},
  {830, 830, 830, 830, 830, 830, 830, 830},
  {830, 830, 830, 830, 830, 830, 830, 830},
  {830, 830, 830, 830, 830, 830, 830, 830},
  {830, 830, 830, 830, 830, 830, 830, 830},
  {830, 830, 830, 830, 830, 830, 830, 830},
  {830, 830, 830, 830, 830, 830, 830, 830}
};

void setup()
{
  Serial.begin(9600);
  delay(50);
  ShowData(0, 0); // 850
  ShowData(6, 0); // 830
  ShowData(2, 1); // 780
}

void ShowData(int Col, int Row)
{
  int v1;
  v1 = DefaultFuelMap[Col][Row];
  Serial.println(v1);
  delay(50);
}

void loop()
{

}

When I use PROGMEM on the array I get the following results output to the serial monitor:
1542
1542
0

When I remove PROGMEM I get the correct data:
850
830
780

It does the same on a mega 1280 and 2560, I'm a bit stuck as to why it's happening, any ideas?

2

Because PROGMEM is in a different address space, accessed via special instructions.
Have a look at the PROGMEM page in the reference.

3

Thanks AWOL, will do

4

another hint: pgm_read_word_near()