mega88 debugWIRE default state

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Hi

can't find in spec at the moment. Is debugWIRE disabled by default for brand new chips from factory?

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See the data sheet Memory Programming section Fuse Bits.

data sheet wrote:
DWEN - 6 - debugWIRE Enable - 1 (unprogrammed)
It comes from the factory disabled. You must enable it before using debugWIRE and disable it after you are finished using debugWIRE.

An example using debugWIRE is near the end of this ATMEL video:
http://www.avrtv.com/2008/09/25/...

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To add to what Mike says that means you need to start by having an ISP connection to the AVR where you enbed DWEN (and SPIEN is disabled). As you also need all 6 wires to get back from dW to ISP mode then it makes sense to always have the 6 wire connection from the debugger/programmer.

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Unfortunately while I was designing my PCB I forgot debugWIRE is not JTAG and now must solder 3 extra wires to SMD part to enable debug interface and set fuses :-/

And yeah the most important thing is when you use debugWIRE you need ISP socket (I was trying to save some space on PCB not implementing full ISP).

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Quote:

Unfortunately while I was designing my PCB I forgot debugWIRE is not JTAG and now must solder 3 extra wires to SMD part to enable debug interface and set fuses :-/

So yet another instance where a prototype on a breadboard or strip board would have proved very enlightening ;-)