Re: JTAG question

On Fri, 30 Dec 2005 11:22:18 +0100, "Sagaert Johan" <sagaert.j AT
belgacom.net> wrote:

>Hi
>
>Thanks for the info
>
>I assume that through the JTAG some external flash can also be programmed
>that has been wired to an ARM device.
>

Yes, but you will need specific software for the ARM/Flash device
combination you use. Go to http://www.gnuarm.com and click on
one of the advertisement links. They have software for JTAG + ARM
that can program a wide range of flash devices for a very reasonable
price.

Regards
Anton Erasmus


>"PeteS" <ps@xxxxxxxxxxxxxxxxxxx> wrote in message
>news:1135846324.935227.190570@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>> Sagaert Johan wrote:
>> > I have a jtag programmer for xilinx devices ,is this a standard
>interface ?
>> > Can i use this device to program other devices with a JTAG interface (eg
>> > ARM ) ?
>> > Or do i need a dedicated tjag interface for every Jtag device i intend
>to
>> > use ? (whats the use of a JTAG standard then ?)
>> >
>> > Johan
>>
>> The standard JTAG interface is for test (JTAG stands for 'Joint Test
>> Action Group'). The IEEE 1149.1 standard is for that. The 1532 standard
>> [IEEE Standard for Boundary-Scan-based In System Configuration of
>> Programmable Devices (IEEE 1532)] at
>> http://grouper.ieee.org/groups/1532/ specifies using the JTAG interface
>> in a standard way for such things as ISP FPGAs.
>>
>> The method used by various cores may or may not actually program that
>> device - often it loads RAM or programs attached flash. There are
>> 'standards' for these interfaces in terms of protocol (ARM uses a
>> particular [wiggler] interface for this and debug functionality, MIPS
>> uses EJTAG, for instance).
>>
>> At the physical layer, these devices are all roughly the same for the
>> JTAG portion (with the notable exception of TRST on Xilinx and a
>> number of other mfr's devices) but those other functions (accessing
>> internal debug registers for runtime ICE, for instance) requires other
>> pins. ARM requires the reset signal to be operated by the JTAG
>> debugger, as yet another example.
>>
>> Note that the JTAG standard is a standard. It's all the things built on
>> top of it that aren't.
>>
>> Cheers
>>
>> PeteS
>>
>
.

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