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Altera_Forum
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12 years ago

alt_read_flash too slow?

I have NIOS-II processor, compiled with Quartus 12.0 I was wondering if the following performance is reasonable: When I call alt_read_flash and read an entire flash block (256KBytes) I measure t...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

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On the contrary, when the NIOS loads the firmware from the same flash it takes around 0.1 second.

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The firmware size is about 2.5MBytes so my calculation about the read speed during boot takes that into acount.

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The flash device I'm using is epcs128.

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2.5MB / 0.1s = 25MB/s

DCLK fMAX of EPCS128 during fast read is 40MHz (which is only 5MB/s if you ignore overhead).

So, something doesnt add up. Can you clarify?

Since you're already using SignalTap, configure it to capture the bootloader sequence and see if it is getting significantly better read timing than your runtime performance. This will simply indicate if you have a problem that you might slightly improve through software optimization.