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Re: Debugging from ROM
- From: Bart Veer <bartv at ecoscentric dot com>
- To: rich at charmedlabs dot com
- Cc: ecos-discuss at sources dot redhat dot com
- Date: Thu, 13 Mar 2003 16:43:56 +0000 (GMT)
- Subject: Re: [ECOS] Debugging from ROM
- References: <ALEFICMPOAICDGJBCPJEGEEHCCAA.rich@charmedlabs.com>
>>>>> "Rich" == Rich LeGrand <rich at charmedlabs dot com> writes:
Rich> Thanks for the information!
Rich> The reason we are considering this is because there is some
Rich> flexibility in our target system. i.e. the flash is mapped
Rich> into the processor's address space through some fpga logic
Rich> so we can intercept writes to the flash address space,
Rich> remember the address, store the result and return the result
Rich> when a read. Surprisingly it is only about 20 lines of HDL
Rich> code (and simple enough for me to write :) Currently, it can
Rich> "alias" 16 words in flash (do you think this is enough?) A
Rich> control bit in a register can enable or disable the aliasing
Rich> (when disabled the flash contents are "restored")
Rich> Agreed this is probably not mainstream, but not too many
Rich> assumptions are made -- only that the target system has some
Rich> programmable logic and that the CE to the flash device is
Rich> provided by the programmable logic. (and that the logic has
Rich> access to the address and data signals -- but this is
Rich> usually the intent with onboard programmable logic) And it
Rich> seems like fpgas are becoming more popular for even
Rich> lower-end systems.
16 breakpoints should be fine for normal usage. This approach to
implementing breakpoints certainly sounds interesting, but there is
still the problem of getting the code into the flash quickly for the
normal development cycle. Do you have any plans for that?
Bart
--
Bart Veer eCos Configuration Architect
http://www.ecoscentric.com/ The eCos and RedBoot experts
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