Has anyone had success moving RTCS Rx/Tx buffers to external memory?
On my board design I have some external SRAM available which I have configured the FlexMemory for and its works well (according to my memory tests). I've moved several of my application memory pools to the SRAM and they function as expected.
I have had some partial success moving some of the RTCS partitions out to the external SRAM by defining a memory pool using global _RTCS_mem_pool. That has worked fine.
But when I try to move the actual Rx/Tx buffers to the FlexMemory ( by defining _BSP_sram_pool and the user_config.h defines, see code snippet from macnet_init.c) I dont get any response for TCP stack.
#if BSPCFG_HAS_SRAM_POOL && BSPCFG_ENET_SRAM_BUF
buf_ptr = _mem_alloc_system_from(_BSP_sram_pool, rxsize + txsize + ssize + lsize);
#else
buf_ptr = _mem_alloc_system_uncached(rxsize + txsize + ssize + lsize); // temporary fix for cache problems... previously _mem_alloc_system
endif
Its likely that its some caching related issue, but I find it hard to find documentation on how to disable cacheing on FlexMemory (or sections of it).
I tried the user_config MQX_USE_UNCACHED_RAM but its conflicts with my lw_mem_allocs that I use and I'm loathe to give up because of shared app code that I use with another board running a Kinetis K21.
I'm using MQX 4.0.2 on a Kinetis K60
