Datasheet

ATmega323(L)

1457E–11/01

Capture-DR controller state. The Bypass register can be used to shorten the scan chain

on a system when the other devices are to be tested.

Device Identification Register Figure 87 shows the structure of the Device Identification register.

Figure 87. The format of the Device Identification register

Version Version is a 4 bit number identifying the revision of the component. The relevant version

numbers are shown in Table 55.

Part Number The part number is a 16 bit code identifying the component. The JTAG Part Number for

AVR devices are listed in Table 56.

Manufacturer ID The manufacturer ID for ATMEL is 0x01F (11 bit)

Reset Register The Reset Register is a Test Data Register used to reset the part. Since the AVR tri-

states Port Pins when reset, the Reset Register can also replace the function of the

unimplemented optional JTAG instruction HIGHZ.

A high value in the Reset Register corresponds to pulling the external Reset low. The

part is reset as long as there is a high value present in the Reset Register. Depending

on the Fuse settings for the clock options, the part will remain reset for a Reset Time-

Out Period (refer to Table 6 on page 27) after releasing the Reset Register. The output

from this Data Register is not latched, so the reset will take place immediately, as shown

in Figure 88.

MSB LSB

Bit 31 28 27 12 11 1 0

Device ID Version Part Number Manufacturer ID 1

4 bits 16 bits 11 bits 1 bit

Table 55. JTAG Version Numbers

Version JTAG Version number (Binary digits)

ATmega323 revision B 0010

Table 56. AVR JTAG Part Number

Part number JTAG Part Number (Hex)

ATmega323 0x9501