03-04-2016 11:15 AM
What is the right address of QSPI flash memory to access(read & write) with DMAC (DMA ps) on ZC702 board?
I'm confused with QSPI address.
When I look system.hdf file on SDK(Vivado 2015.2), QSPI address is 0xE000D000, and LQSPI address is 0xFC000000.
how they are different?? The board I use is ZC702 has one 16MB QSPI flash.
If I want to access to the flash memory to write or read, which address is the base address?
For example, if I want to read data from 0x800000 in the QSPI flash memory, the source address is 0xE000D000 + 0x800000?
or 0xFC000000 + 0x800000?
And if one of two is right, the right one can be also available with DMAC (DMA ps)?
I have looked at some example source code for both with DMAC and non-DMAC, but I could not understand..
And here is one more this that makes me confused.
when you look at 7th slide of this document
Address 0xFC000000 is not Linear QSPI, but OCM's address.
Which one is right one?
I'm very confused.
Please help me.
03-06-2016 07:02 AM
03-06-2016 07:02 AM
03-08-2016 01:14 PM
Based upon above link, it seems like only reading operation is possible....
I haven't tested yet...
Is there anybody who have done this already??
03-09-2016 12:24 PM
if you need to ask this, then it would take really long to explain it.
it would be NOT FEASIBLE to implement writing in linear mode, too complex and useless or even dangerous..
03-09-2016 01:44 PM - edited 03-09-2016 01:44 PM
Can you give me some links or docs that I can roughly figure it out why writing operation with LQSPI is not available?
03-10-2016 12:00 AM
you need 10+ years experience to not ask this question. I can not give you those years. sorry for that.
Linear mode for serial memories is made for XiP execute in place, where the read access is fast enough to be usable.
NOR flashes have limited endurance and very slow writes and do not support byte writing, so while possible implementing linear writes is not feasible as I said.
This applies for LQSPI and serial NOR Flash, if you have HyperRAM then you can have linear memory space, that makes again sense, but for HyperFlash sharing the same HyperBus interface linear writes again do not make sense.