Re: Switchless ROMs

From: Hegedűs István <>
Date: Fri, 30 Dec 2016 11:16:26 +0100
Message-ID: <>
The FPGA doesn't have much RAM so there is no point in using it to store ROM 
images. This is the reason why I have switched to Papilio Pro board from 
Papilio One. The Papilio Pro has 64k usable internal SRAM which is more than 
the previous board has, however still not enough. That is the reason why I 
had to do this trick to store ROM images in the same flash chip which the 
FPGA uses to store its config. In case of the Papilio Pro the FPGA 
configuration flash chip is tied to IO pins of the FPGA so after the core 
has started up the flash chip can be used by internal user logic. It has 
more than enough space (64Mbit).


-----Original Message----- 
From: Michał Pleban
Sent: Monday, December 26, 2016 11:53 PM
Subject: Re: Switchless ROMs


Hegedűs István wrote:

> (ROMs are uploaded to SDRAM from the FPGA's flash chip during boot).

I understand they are uploaded from some Flash chip that is on the
development board, not from the FPGA itself? Because otherwise, why the
FPGA itself could not act as a ROM chip?


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Received on 2017-01-01 23:01:24

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