Re: [Balloon] Accessing NOR flash from Linux

On 08/06/2011 14:43, Patrick Doyle wrote:
> I think I'll go down the path of enabling access to the FPGA partition
> of the NOR flash... at least until the "too hard" LED turns on. Then
> I'll start looking at the bbl path recommended by Wookey. I'm
> avoiding the bbl path right now because my USB<->RS232 converter only
> works natively on my MacBook, and I deemed it more difficult (and less
> fun) to figure out how to make bbl run on the MacBook, than it would
> be to go hack kernel code.

Don't worry too much about bbl. Clever and useful though it is, it's a
wrapper round existing procedures using the serial port and JTAG ports
mostly. My world suffers from sufficient dependency rot that I often
find it easier to work with the bare metal - see below.

My favourite ways of programming the NOR Flash:
- serial into the bootldr with 'load flash 0x.....' and an XMODEM
transfer. Pretty slow at 115kbaud but simple and reliable.
- if the wind's blowing in the right direction, OpenOCD to talk to the
JTAG port on the Balloon and program the NOR Flash that way. Quicker,
capable of 20kbytes/sec or more, but requires more complex hardware and
software.

Both of these should work without too much grief on the Mac. I've used
them both, though I've found USB-serial adapters on my Mac to be less
than perfect.

Chris

--
Chris Jones - chris@martin-jones.com
Martin-Jones Technology Ltd c/o Element Energy Ltd
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