08-08-2019 05:29 PM
There are many applications where 1GB of DDR is not required for a simple linux host .
I need to run a small 2MB linux image on a microblaze in an A7. I am considering using a 8MB HyperRAM connected via an AXI connection. HyperRAM is a bit like an eMMC bus interface- small pin count.
For this to work , my HyperRAM core will need to look like an AXI4 slave that can work with the line lengths requested by the cache controller. Additionally, there will need to be some Block RAM (LMB) initialized to get the whole thing started and load the HyperRAM from spiFLASH .
I have done a few Microblaze + FreeRTOS designs using large slabs of BlockRAM( which works as a dual port memory for I and D) .
Has anyone tried what I describe above ?
08-13-2019 02:07 AM
We have designed a pcb with one artix 7 fpga and 2 hyperrams on it.
We have 2 microblaze running inside with each cpu having one hyperram with cahce access.
Each cpu can also read from both hyperrams.
We have bought the ip core form synaptic labs xilinx edition with no problems.
This core i running with 100mhz for the microblaze and 100mhz clock for the rams.
Theay are working on increasing the clock speed for the rams.
08-13-2019 02:36 AM
thanks for the report. That is encouraging for me. I am using S27KS0641 type. I will write my own core for them although that will take a little time. I see 128Mb are becoming available.
08-13-2019 03:30 AM
Cypress has a free ip core but is not optimized for fpga. you could get it as a good starting point.
I tried it at first but could not get it to work. And since i did not have the time to write my own we decided to purchase one.