ATmega128 datasheet(258/386 Pages) ATMEL

номер детали	ATmega128

подробное описание детали	8-bit Microcontroller with 128K Bytes In-System Programmable Flash

PDF	386 Pages

Scroll/Zoom	100%

производитель	ATMEL [ATMEL Corporation]

домашняя страница	http://www.atmel.com

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258 / 386 page

258

2467S–AVR–07/09

ATmega128

Figure 126. Additional Scan Signal for the Two-wire Interface

Scanning the RESET

The RESET pin accepts 5V active low logic for standard Reset operation, and 12V active high

logic for High Voltage Parallel programming. An observe-only cell as shown in Figure 127 is

inserted both for the 5V Reset signal; RSTT, and the 12V Reset signal; RSTHV.

Figure 127. Observe-only Cell

Scanning the Clock

Pins

The AVR devices have many clock options selectable by fuses. These are: Internal RC Oscilla-

tor, External RC, External Clock, (High Frequency) Crystal Oscillator, Low-frequency Crystal

Oscillator, and Ceramic Resonator.

Figure 128 shows how each Oscillator with external connection is supported in the scan chain.

The Enable signal is supported with a general boundary-scan cell, while the Oscillator/Clock out-

put is attached to an observe-only cell. In addition to the main clock, the Timer Oscillator is

scanned in the same way. The output from the internal RC Oscillator is not scanned, as this

Oscillator does not have external connections.

Pxn

PUExn

ODxn

IDxn

TWIEN

OCxn

Slew-rate limited

SRC

From

cell

ClockDR

ShiftDR

cell

From system pin

To system logic

FF1

ATmega128 датащи(PDF) 258 Page - ATMEL Corporation