ATmega128 datasheet(49/386 Pages) ATMEL

Teilenummer	ATmega128

Bauteilbeschribung	8-bit Microcontroller with 128K Bytes In-System Programmable Flash

PDF	386 Pages

Scroll/Zoom	100%

Hersteller	ATMEL [ATMEL Corporation]

Direct Link	http://www.atmel.com

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49 / 386 page

2467S–AVR–07/09

ATmega128

JTAG Interface and

On-chip Debug

System

If the On-chip debug system is enabled by the OCDEN Fuse and the chip enter Power down or

Power save sleep mode, the main clock source remains enabled. In these sleep modes, this will

contribute significantly to the total current consumption. There are three alternative ways to

avoid this:

•

Disable OCDEN Fuse.

•

Disable JTAGEN Fuse.

•

Write one to the JTD bit in MCUCSR.

The TDO pin is left floating when the JTAG interface is enabled while the JTAG TAP controller is

not shifting data. If the hardware connected to the TDO pin does not pull up the logic level,

power consumption will increase. Note that the TDI pin for the next device in the scan chain con-

tains a pull-up that avoids this problem. Writing the JTD bit in the MCUCSR register to one or

leaving the JTAG fuse unprogrammed disables the JTAG interface.

ATmega128 Datenblatt(PDF) 49 Page - ATMEL Corporation