ATmega165 datasheet(269/336 Pages) ATMEL

269 / 336 page

269

ATmega165/V

2573G–AVR–07/09

Reset Register

The Reset Register is a Test Data Register used to reset the part during programming. It

is required to reset the part before entering Programming mode.

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 “Clock Sources” on page 24) after releasing the Reset Register. The out-

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

shown in Figure 100 on page 213.

Programming Enable Register

The Programming Enable Register is a 16-bit register. The contents of this register is

co mp are d

the

p r og ra mm ing

en ab le

s i g n a t ur e,

bina ry

cod e

0b1010_0011_0111_0000. When the contents of the register is equal to the program-

ming enable signature, programming via the JTAG port is enabled. The register is reset

to 0 on Power-on Reset, and should always be reset when leaving Programming mode.

Figure 123. Programming Enable Register

TDI

TDO

ClockDR & PROG_ENABLE

Programming Enable

0xA370

ATmega165 Datasheet(PDF) 269 Page - ATMEL Corporation