[PULPissimo] How to resize memory correctly
#1
Hi,

I'm working on a design based on PULPissimo and we're about to tape-out a test chip. But the technology that we're working on is pretty "big" (HC90L from SK Hynix), thus 512KB of total memory takes way too much area. Therefore I wanna reduce the total size of memory into half (256KB). 

In order to do that, I modified these:
- pulp_soc.sv (half size for both L2_BANK_SIZE and L2_BANK_SIZE_PRI).
- fpga_settings.mk (for a test build on FPGA)
- soc_interconnect.sv (for memory address, reduce PER_END_ADDR of PRI_L2_CH1, PRI_L2_CH0 and TCDM_END_ADDR).
- pulp-configs/configs/chips/pulpissimo/pulpissimo.json (memory size for sdk I guess)
The result is pretty bad. Simulation shows lots of "a request with unknown address". I guess I was wrong somewhere, or missed something.

And  since I disable FPU to reduce SoC size (I don't really need it), I also change ri5ky_v2_fpu_1_10 to a custom core that doesn't have FPU arguments.
-   "isa" from "rv32imfcXpulpv2" to "rv32imcXpulpv2"
- Remove "--fpu", "--fpud" and "--shared-fpu" from "gv_isa"
- Remove "compiler_args"
Eventhough, the final binary generated by SDK still has FPU related instruction, which will resulted in "Illegal instruction" exception while execute the program. 

Can you please help me out with above issues? Thank you very much in advance.
Regards.
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[PULPissimo] How to resize memory correctly - by gideros - 12-16-2019, 02:21 AM

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