Lpc2000

John, 

> The Signum JTAGjet claims download speed in excess of 1 
> MByte/sec, not 1Mbit/sec.

You can't get anywhere near that on ARM7TDMI-S parts which we are
dicussing, so this claimed speed is irrelevant in this instance.

> From the Signum web site 
> http://www.signum.com/Signum.htm "Actual speed 1.062 
> Mbyte/sec tested with ARM Evaluator 7T board and 600 MHz 
> Pentium III PC with USB 2.0 port. Faster PCs may yield faster 
> downloads."

Yes, the Evaluator-7T is a hard core and TCK can be clocked at 10MHz in
this case (or greater in some cases).  However, not all ARM parts
support this.

> Since the JTAGjet uses USB 2.0 this is reasonable, provivded 
> the target device and connections can hold up.

USB 2.0 conformance does not imply a high speed device.  CrossConnect is
a USB 2.0 full speed device. Is the JTAGjet a full speed or high speed
device?  Or are you making the assumption that all USB 2.0 devices are
high speed and equating 2.0 devices to be inherently faster than 1.1
devices?  USB 1.1 full speed devices can support 1Mbyte/sec data rates
over USB so the statement "Since the JTAGjet uses USB 2.0 this is
reasonable" holds no weight.

> Leaving aside the issue of delays introduced by programming 
> Flash, which many developers do not need to bother with 
> during development if all their code fits into RAM, the 
> claimed speed supports what many developers welcome and which 
> was mentioned by Chris: rapid reading of data blocks at breakpoints.

We are dicussing speed on the LPC2000--which, by definition, people *do*
need to worry about because many devices have limited RAM, no external
bus, but lots of flash (like the 2148, for instance).  The claimed speed
avantage of the JTAGjet is put to the test in this instance and is below
even the lowly speed of a wiggler.  The original poster said his code
did not fit in RAM and he needed to put in in flash--so the claimed
speed advantage of the JTAGjet is worthless (in this instance).

> The Signum JTAGjet also claims compatibility with all major 
> ARM debuggers and another version of the JTAGjet supports ETM.

...your point?

-- Paul.