1-Port ROM only outputting one byte

Question

Hello all,

I used the Mega-Wizard in Quartus to instantiate a single clocked 1-Port ROM block, 64-bit wide, 256 words deep.

It's for a Cyclone II FPGA.

I created a Memory Initialization File to give it starting values.

Here's the beginning of it below:

DEPTH = 256; -- The size of memory in words

WIDTH = 64; -- The size of data in bits

ADDRESS_RADIX = HEX; -- The radix for address values

DATA_RADIX = HEX; -- The radix for data values

CONTENT -- start of (address : data pairs)

BEGIN

0 : 14 21 A1 4B 68 00 CA 9F;

1 : 19 D8 83 23 2B 90 28 4E;

I place the 64-bit output into a register, and send it out serially to another device, MSB first.

But when I check the serial stream, I see 00s except for the least significant byte.

So for Address 0 I see 0000000000000014 stream out, and for Address 1 I see 0000000000000019.

I don't see any warnings or errors associated with the memory after compilation.

Has anyone seen something like this before?

altera_forum · Answer

How do you know its the rom and not the logic that drives the serial interface?

altera_forum · Answer

Hi Awann,  this happens if you uses spaces between the bytes. try to write all hex without spaces.

altera_forum · Answer

--- Quote Start ---

Hi Awann,

this happens if you uses spaces between the bytes. try to write all hex without spaces.

--- Quote End ---

Thanks Duesterberg! Problem solved.

I swear I had seen a .mif example with spaces in between the bytes, but obviously I was incorrect.

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