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AVR using JTag pins

Hi,

Could I use AVR JTag pins in my application circuit when debugging using JTag?

Adding resistors to separate?

Thanks!

Reply to
terry
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These comments are intended to be my own opinion and they may, or may not be shared by my employer, Atmel Sweden.

"terry" skrev i meddelandet news: snipped-for-privacy@posting.google.com...

JTag?

I do not think so.

--
Best Regards
Ulf at atmel dot com
Reply to
Ulf Samuelsson

So I cannot debug when I use SPI in ATMega16!

Reply to
terry

On the ATmega16, the SPI port is on PB4-7 and the debug port in on port PC2-5.

What is the problem again ???

Yes, you will lose port bits PC2-5 when using the JTAG port.

hamilton

Reply to
hamilton

Thanks!

Reply to
terry

I found in the JTagIce manual there is a section saying the following:

Figure 2-2 shows which JTAG lines should be connected to the target AVR to ensure correct operation. To avoid drive contention on the lines, place series resistors between the JTAG lines and external circuitry. The value of the resistor should not exceed the maximum ratings and sink or source to much current. See Section 5.4 for a detailed description of the hardware.

Is it true to place series resistors between the JTAG lines and external circuitry so that I can debug the IO pins using JTagICE?

Reply to
terry

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