platform flash as storage?

- J
- John Williams
  
  Contact options for registered users
posted
20 years ago

Tue, Sep 16, 2003 11:03 PM

Hi folks,

We're looking for a high density serial flash part to hold microblaze uclinux kernel and file system images. The problem with commodity serial flash parts (SST, Nexflash etc) seems to be that they aren't really available in high densities (~4 - 8 MB) yet. If someone can correct me on this then please do!

Anyway I'm wondering if we could potentially use a Xilinx platform flash part to hold both an fpga configuration and "random data". I know about SystemACE, but we can't afford that many pins. For the same reason I don't want to use regular parallel flash parts.

The idea is that the FPGA configures with a microblaze bitstream, contained in the BRAM is a small bootloader that then sucks the kernel and filesystem image (potentially several megabytes) out of serial flash, copies it into external memory, then off it goes.

With the serial flash parts I've seen so far, we'd need at least 2 or 3 of them to fit everything we need (plus level translators since this has to share an IO bank with 2.5V DDR, whereas serial flash devices generally seem >2.8V).

It would be lovely if we could just put an 8MB xilinx platform flash part on the board and use it to store both the configuration and our software images.

Any thoughts?

Thanks,

John

- A
- Antti Lukats
  
  Contact options for registered users
Vote on answer
posted
20 years ago

Wed, Sep 17, 2003 5:38 AM

sorry, I am waiting also for an FPGA with config loader from MMC card! not avail. systemace is nice. you could do systemace-mmc controller with some small fpga not as nice as systemace, but would work. using platform flash for linux image storge would be real tricky at least. might be theoreatically possible but you would need to use JTAG to get the data asmuch as I understand., or add small logic that disables the configuration of the FPGA and restart config, and 'fetch' the stuff 'appended' to bitstream this would be fast download.

antti

- L
- Lorenzo
  
  Contact options for registered users
Vote on answer
posted
20 years ago

Wed, Sep 17, 2003 7:38 AM

"John Williams" ha scritto nel messaggio news:bk841k$7hf$ snipped-for-privacy@bunyip.cc.uq.edu.au...

I think it's possible! You can store your custom code as it was a separate "firmware", like if you have a second FPGA attached. Then the platform flash will do the rest. Look at the app notes that show how to connect more than a FPGA to a configuration flash/PROM.

--
Lorenzo

- J
- jetmarc
  
  Contact options for registered users
Vote on answer
posted
20 years ago

Wed, Sep 17, 2003 4:53 PM

3 years ago I had no trouble purchasing the Atmel Serial Dataflash AT45D161, which is 2 MBytes big. Certainly the higher densities became available in the meantime.