ATMEGA128-16AU SL383 Atmel, ATMEGA128-16AU SL383 Datasheet - Page 308

• Manufacturer Part Number: ATMEGA128-16AU SL383
• Manufacturer: Atmel

Reset Register
Programming Enable
Register
308
ATmega128
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
Sources” on page
not latched, so the reset will take place immediately, as shown in
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 leav-
ing Programming mode.
Figure 147. Programming Enable Register
TDO
TDI
D
A
A
T
37) after releasing the Reset Register. The output from this Data Register is
$A370
=
ClockDR & PROG_ENABLE
D
Q
Programming enable
Figure 123 on page
2467S–AVR–07/09
254.
“Clock