Lpc2000

Tom, Guido,

 From the BDI2000 this may be an optional signal. On the LPC21xx it must 
be used.
The RTCK signal is described in the ARM7 TDMI-S manual that can be found 
on the ARM website.
Check the website for a link or browse the archive - it's been mentioned 
a few times.

If you do not use the RTCK signal - or cannot use that signal because it 
is unsupported on your JTAG debugger - make sure that the JTAG CLK is 
lower than 1/6 of the CCLK of the lpc21xx, otherwise the timing is 
screwed. See the ARM manual for detailed information - it even contains 
some schematics on how the RTCK is generated in the processor.

Regards,

    Rob

Tom Walsh wrote:

>Soentgerath, Guido wrote:
>
>  
>
>>Hello all,
>>can someone give me an explanation for RTCK  or  a hint where I can find
>>some more infos about this signal ?
>>Thanks in advance!
>> 
>>
>>    
>>
>RTCK is an optional JTAG signal.  According to the Abatron BDI2000 manual:
>
>"Adaptive clocking is a feature which ensures that the BDI2000 never 
>loses synchronization wih the target device, whatever the target clock 
>speed is.  To achive this, BDI2000 uses two signals TCK and RTCK.  When 
>adaptive clocking is selected, BDI2000 issues a TCK signal and waits for 
>the Returned TCK (RTCK) to come back. BDI2000 does not progress to the 
>next TCK until RTCK is received."
>
>
>TomW
>
>  
>