On Tue, Mar 4, 2008 at 4:16 AM, Nilanjan Goswami
> Hi Folks,
> Thank you all very much for resolving the XDS510 USB JTAG connector
> problem DaVinci EVM.
> I have searched for the fast JTAG in the internet, but I am really
> perplexed. I found two different variations of the hardware (XDS560),
> USB based and PCI based from different vendors.
> 1. Can in anybody tell me why XDS560 is faster than XDS510?
The original XDS510 had a TCLK rate of 10+ Mhz. The XDS560 has a TCLK
rate of "up to 35 Mhz". This rate is variable and is dependent on the
particular target and the signal quality of the JTAG connection. TCLK
is the serial clock that transmits data to and from the target - it is
not the only performance factor, but it is a good indicator. Some
current XDS510's have a TCLK faster than 10 Mhz, but I am not sure of
the current rates available. The other factor is your definition of
high performance. In some cases it 'all about download speed' [your
are debugging a system with 8 MB of code and it is far from finished].
The principal architectural difference between the 2 is that the
XDS560 has a c6x processor on the emulator [PCI board or USB 'box']
that takes high level commands from the host and then performs
multiple low level JTAG scans independent of the host processor. The
core XDS560 architecture is defined by TI.
Modern XDS510 USB emulators have an evolved XDS510 proprietary
architecture that performs some processing in the USB box. SD
probably has the most advance XDS510 emulator technology.
Another performance issue is with cheap XDS510 USB emulators. They
have a 10 Mhz TCLK but do not perform any processing on the remote
'USB box'. They are adequate for simple debug but can be intolerable
for loading large programs or performing multiple single steps.
NOTE: Only the XDS560 supports HSRTDX and *might* be upgradeable to
support the Trace feature [if you have the $$$].
> 2. Which one should I purchase USB based or PCI
If you have one machine in your lab and you always debug on that
machine, a PCI emulator is okay. If you ever need to use the emulator
at different locations or with laptops, USB is the way to go. Also
for small workgroups, you can 'move the emulators around' based on who
needs them. If you have multiple emulators and one fails, you can
verify it very easily. Personally, I would choose a USB emulator.
Although I haven't performed benchmarks, I have seen similar
performance between a BlackHawk USB XDS560 and a TI PCI XDS560 [I do
not notice any difference].
NOTE: Compare some benchmark data on 'the things that you care about'.
> 3. I will be using DaVinci DM6446 EVM from spectrum
digital. From your
> experience can you tell me which device will give me best performance
> for hardware debugging?
My preferences would be:
1. XDS560 PCI.
2. any XDS560.
You may be able to get a vendor to run some provided benchmarks on a
DaVinci target for you - especially if you plan to buy more than one
You will be much happier with an XDS560 on that device.
> Thanking you in advance,
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