Datasheet

281

2466T–AVR–07/10

ATmega16(L)

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 set-

tings for the clock options, the part will remain reset for a Reset Time-out Period (refer to “Clock

Sources” on page 25) 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 115 on page 230.

Programming Enable

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

to the programming enable signature, binary code 1010_0011_0111_0000. When the contents

of the register is equal to the programming 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 140. Programming Enable Register

TDI

TDO

ClockDR & PROG_ENABLE

Programming Enable

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