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Adventurer
Adventurer
275 Views
Registered: ‎06-22-2018

OCM addresses in lscript.ld

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In UG585, it states Zynq-7000 has 256K OCM. Upon entering the user mode, the RAM is located at 0x0000_0000 to 0x0002_FFFF and FFFF_0000 - FFFF_FFFF. But my generated project shows:

1.png

The total OCM is less than 256K, what is the other bytes preserved for?

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Xilinx Employee
Xilinx Employee
244 Views
Registered: ‎09-04-2012

Re: OCM addresses in lscript.ld

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That space is used to "park" Core 1. There is code that keeps Core 1 in WFE state in case it wakes up before an OS has a chance to load some code for it.

Regards,

Christophe

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Xilinx Employee
Xilinx Employee
245 Views
Registered: ‎09-04-2012

Re: OCM addresses in lscript.ld

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That space is used to "park" Core 1. There is code that keeps Core 1 in WFE state in case it wakes up before an OS has a chance to load some code for it.

Regards,

Christophe

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Scholar ericv
Scholar
228 Views
Registered: ‎04-13-2015

Re: OCM addresses in lscript.ld

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@diverger

You may want to change the script to declare 256K in the OCM instead of 64K as it is in yours:

ps7_ram_1    0xFFFC0000   0x3FE00

And yes, the upper 256 bytes shouldn't be touched as @cch indicated, as they are used during boot-up... unless this area is tagged as NOLOAD.

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