Lpc2000

Hello,

Looking for a solution to the "secondary jtag problem", I have 
discovered that in some cases both jtag interfaces seems to be 
active simultaneously! 

The tests were performed both on IAR "Kick-Start" boards and Ashling 
EVBA7, using IAR/Segger j-link and Segger "J-mem" JTAG software.

I programmed the flash via UART0 with my application sw. The sw first 
sets PINSEL1 register to 0x55400000 (to enabling secondary JTAG). 
Using a console interface, I can read & change any memory / register.

Before power up, I enabled JTAG1 (DBGSEL & RTCK high). The JTAG 
worked as expected.

I then changed to secondary jtag by moving jumpers on the boards, 
WITHOUT resetting the uC. As soon as the jumpere where in place, I 
could now re-establish jtag connection over the secondary interface. 
And also switch back to the first one.

I could also disable/enable the secondary interface by writing 
0x00000000/0x55400000 to PINSEL1. This did not affect jtag1.

After moving to jtag2 (DBGSEL low), and then pressing RESET, I could 
always access secondary jtag as long as the power was not removed. 
Still I could switch to the primary jtag port.

I had no problem doing code download and debugging over secondary 
jtag, using IAR C-spy, as soon as the connection was established. But 
as in previous cases, most times communication must first be 
established over primary jtag after power on.

This behaviour does not correspond to the Philips documentation!

Connecting or not connecting RTCK to the j-link dongle does not seem 
to matter.

Any explanation or other experiences????

Jon