Determine the Minimum Size of QFlash Enough for DFU Topic is solved

Technical questions regarding the xTIMEcomposer, xSOFTip Explorer and Programming with XMOS.
dkybchoi
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Determine the Minimum Size of QFlash Enough for DFU

Postby dkybchoi » Fri Sep 01, 2017 4:17 pm

HI ,
If only one factory image and one upgrade image are required and no data partition, Is the minimum size of QFlash must be greater than the boot partition size calculated by below equation?

boot partition size = loader size + maximum size of factory image + maximum size of upgrade images + padding to sector boundaries

Where
maximum size of factory image = number of xCORE tiles * xCORE SRAM size
maximum size of upgrade images = (number of xCORE tiles * xCORE SRAM size) * number of images to be held in flash concurrently

We are using XU224-1024-XXX which xCORE SRAM size is 256KB . It means "maximum size of factory image" and "maximum size of upgrade images" are both 4 * 256KB = 1MB

Actually, the factory image size will be always less than 1MB , so is it possible to adjust the sector boundary of factory Image to be less than 1MB and so we can use a smaller size QFlash ?

Thanks


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mbruno
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Joined: Thu Aug 24, 2017 2:48 pm

Postby mbruno » Fri Sep 01, 2017 9:48 pm

Hi dkybchoi,

I believe that when xflash creates the flash image for you, it assigns the image boundaries addresses dynamically based on the actual size of your binaries. It should not allocate each image a full 1 MiB if the images are smaller than that. The sector boundaries, however, are a function of the flash chip itself - 4 KiB is a typical sector size. Therefore expect the starting address of each image (factory and upgrade) to be at a multiple of 4 KiB or whatever the sector size of your flash is.

That said, I am unable to find any quad SPI flash chips that are smaller than 4 MiB. Or are you planning on using a traditional SPI flash (not quad SPI)?

Mike
dkybchoi
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Posts: 16
Joined: Thu Sep 29, 2016 3:03 am

Postby dkybchoi » Mon Sep 04, 2017 3:53 pm

Hi Mike,

Thanks for your answer.

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