Occasional ContributorMax10 programming external flash
After much trial and error, I have it working. Now I can write to and read from/erase the memory. Basically, I found and error in the Intel example design. Once I corrected it, everything works.
For anyone else who might try it using Nios.
First you have to do a write enable like this:
IOWR(EXT_FLASH_AVL_CSR_BASE,0x7,0x00000006);
IOWR(EXT_FLASH_AVL_CSR_BASE,0x8,0x1);then you can write 0xabcd1234 into the memory like this(this is where the example design had mistakes):
IOWR(EXT_FLASH_AVL_MEM_BASE,0x00000000,0xabcd1234);Then to read it back, do it like this:
IOWR(EXT_FLASH_AVL_CSR_BASE,0x4,0x00000000);
IOWR(EXT_FLASH_AVL_CSR_BASE,0x0,0x00000101);
IOWR(EXT_FLASH_AVL_CSR_BASE,0x5,0x00000003);
return IORD(EXT_FLASH_AVL_MEM_BASE,0x00000000);The most confusing parts are these offsets 0x4, 0x5....etc. I have figured out what most of them are, so I will list them below:
0x0 control register
0x4 operating protocols
0x5 read instructions
0x6 write instructions
0x7 flash command setting
0x8 flash command control(basically always write 0x1 here when writing into the status registers to begin the operation)
0x9 flash command address register
0xA flash command write data
0xC flash command read data
Why this isnt included in any documentation I have no idea. Basically, once I understood what these offsets were doing I had it up and running in just a few minutes. Hopefully these short notes help the next person.
