how setting xmos boot from spi by other pins

Sub forums for various specialist XMOS applications. e.g. USB audio, motor control and robotics.
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hushange
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how setting xmos boot from spi by other pins

Post by hushange »

from the datasheet of xmos, it boot from spi flash with X0D00 X0D01 X0D10 X0D11,
but now i want to know the following:
1. whether xmos can boot from spi flash with other pins, not x0d00 x0d01 x0d10 x0d11, such as use x0d24 x0d35 for spi booting.
2. how to implement it

is somebody has clues?

many thanks
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infiniteimprobability
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Post by infiniteimprobability »

It's possible, but it means blowing the OTP. This is because the pins used by the built-in bootloader are defined in ROM which is hard on the chip (it's a software loader).
By programming a custom bootloader into the OTP you can achieve what you want. Something like this was done on the XK-1A board so that X0,1,10,11 were completely free for the user.
HOWEVER, I really don't recommend this. Blowing bootloaders into the OTP and getting it wrong is painful as you can end up throwing a lot of chips (maybe boards too) in the bin. It can be done, but personally I'd look at other ways of freeing IO first!
hushange
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Post by hushange »

get it, thank you a lot.
by the way, whether there is a otp deamo program, so that i can take a trying, just for trying.
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infiniteimprobability
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Post by infiniteimprobability »

Hi,
the code we used for this is the modified boot ROM which is written in assembler and not really fit for publishing (comments/documentation). There are quite a few underlying architectural complexities hidden by this code too so it would need some support to get going, and with the added issue of OTP, it's likely to be a painful route. Again, I'd really recommend to look at alternatives to freeing up or moving I/O. Perhaps we could help with ideas for that?
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Ross
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Post by Ross »

Moving.
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