Hi
I know this must seem obvious, but is there space in your bootloader for
a routine to test the SDRAM?
Cheers
Andrew
On 20/03/2014 21:52, Rick Raffanti wrote:
Hello Caspersphere,
I have a problem unrelated to Casper IP, toolflow, hardware, or
software. But I know this list is full of clever, generous people, so
here goes.
I have an SP601 development board. A dozen, in fact. The board has a
Spartan6, a 16MB flash, and 128MB of DDR2. My design has a MicroBlaze
and an executable which is too large to fit in the on-chip BRAM. So the
idea is to have a bootloader program that does fit in the BRAM, which
then loads the executable out of flash into DDR2, then vectors and
you're off and running.
I've implemented all this, and programmed the flash. And when I
configure the FPGA with its configuration bitstream and a "bootloop"
(this is a Xilinx SDK thing), then I load up the bootloader, everything
works fine. When I power cycle the board, so that the config bitstream
and bootloader executable are loaded up from flash, it works sometimes,
on some boards. But on some boards, almost never. On some boards,
almost always.
I put in a checksum of the executable code- as the bytes are read from
flash and written to RAM I do a checksum on the data read from flash,
and a separate one on the data read back from RAM. The former is always
the same, the latter varies.
So I thought, Oh, the RAM must be in the process of calibration, and I
put in a several-second delay before the flash read/RAM write. But no help.
So, if you have any thoughts, I'd appreciate it. Xilinx tech support is
not very helpful.
Many thanks,
Rick
