Programming interface failed

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ATmega169P has been programmed by AVRstudio v4.18.700 in WinXP SP3 in two ways. Firstly, the ISP method has been used with success, but JTAG programming not possible after ISP!!! The only way to fix this is restart programmer (reconnect AVRdragon). Strange behaviour?

IV

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Quote:

Strange behaviour?

Not if the JTAGEN fuse bit was set to 1.

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Checked, JTAGEN=1.
Cannot take my mind why "prog. mode" drop-down list needed in this case? If the only way to change prog mode from ISP to JTAG is restarting Dragon/programmer...

IV

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Quote:
but JTAG programming not possible after ISP!!!
Because you cleared JTAG with ISP
Quote:
Checked, JTAGEN=1.

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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js wrote:
Quote:
but JTAG programming not possible after ISP!!!
Because you cleared JTAG with ISP
Quote:
Checked, JTAGEN=1.

In AVRstudio programmer JTAG interface was enabled. I don't change default value for JTAGEN fuse.

IV

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1 is disabled, 0 is enabled. If you use Studio then the box ticked means enabled.

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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js wrote:
1 is disabled, 0 is enabled. If you use Studio then the box ticked means enabled.
Yes, but the question is: why JTAG programming not possible after ISP without restarting programmer??? JTAG always enabled for me!!!

IV

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Quote:

why JTAG programming not possible after ISP

Because, during the ISP, you reprogrammed the fuses and switched off the JTAG interface. Why are you surprised that you cannot use JTAG when it is switched off?

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clawson wrote:

Because, during the ISP, you reprogrammed the fuses
No, I'm not! In my device the fuses keep it's default values! I'm looking onto ISP and JTAG as fully independent interfaces for programming. Did you mean that programmer software disable JTAG fuse during the ISP?
When I wrote "Checked, JTAGEN=1", this mean that checkbox enabled in AVRstudio programmer, not fuse value = 1! Of course, fuse value = 0 in this case.

IV

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Quote:

When I wrote "Checked, JTAGEN=1"

Then why did you type JTAGEN=1 if JTAGEN actually =0 ??