2 Replies Latest reply on Jun 26, 2018 7:08 AM by drsy_2254101

    FX3 Expand Data Memory into DMA space?

      It is generally accepted that the data section of code in a 512kB FX3 or FX3s is divided roughly into two halves, the first being program and data memory etc, and the second devoted to DMA. Seeing as this quantity of DMA space is excessive for most applications, the ability to expand data memory into this section is attractive. I've done so without catastrophic failure, but I also have several strange problems which I am working through. Can someone please confirm that the FX3 memory can be divided as such without issue?


      In "fx3.ld":



      I-TCM   : ORIGIN = 0x100      LENGTH = 0x3F00

      SYS_MEM : ORIGIN = 0x40003000 LENGTH = 0x30000

      DATA    : ORIGIN = 0x40033000 LENGTH = 0x12000



      In "cyfxtx.c"


         The MEM heap is a Memory byte pool which is used to allocate OS objects

         such as thread stacks and memory for message queues. The Cypress FX3

         libraries require a Mem heap size of at least 32 KB.


      #define CY_U3P_MEM_HEAP_BASE         ((uint8_t *)0x40045000)

      #define CY_U3P_MEM_HEAP_SIZE         (0x8000)


      /* The last 32 KB of RAM is reserved for 2-stage boot operation. This value can be changed to

         0x40080000 if 2-stage boot is not used by the application. */

      //#define CY_U3P_SYS_MEM_TOP           (0x40078000)

      #define CY_U3P_SYS_MEM_TOP           (0x40080000)